Washington(CNN) President-elect Donald Trump's choice for secretary of state, Rex Tillerson, is facing resistance from a notable quarter -- Republican Sen. Marco Rubio.
Rubio -- who refused to say if he would vote for Tillerson after a day of testimony -- pressed the former ExxonMobil CEO hard Wednesday on a slew of human rights questions, pushing him to denounce the behavior of Russia, China, Saudi Arabia and the Philippines and expressing deep disappointment when the Texan refused to do so.
Rubio's vote could make the difference in Tillerson's progress, as Republicans have only a one-vote margin on the Senate Foreign Affairs Committee and Democrats may not support him. But it is possible, should Tillerson stall in committee, for the Senate to bypass the panel and bring the nomination to the full Senate for a vote.
"This is a very important decision and I recognize the partisan split on the committee and what it means," Rubio told reporters after the hearing. "I'm prepared to do what's right."
The Florida senator -- who lost to Trump in the GOP presidential primary and had heated personal exchanges with him during the campaign -- told Tillerson that "moral clarity" is crucial to US foreign policy and expressed disbelief that Tillerson wouldn't deliver judgments on countries' alleged human rights abuses when information is widely available.
"The position you've been nominated to is, in my opinion, the second-most important position of the US government, with all due respect to the vice president," Rubio said.
When the world sees that "the United States is not prepared to stand up and say, yes, Vladimir Putin is a war criminal, Saudi Arabia violates human rights, it demoralizes these people all over the world," Rubio said.
Rubio wasn't alone on the fence. Sen. Lindsey Graham, a South Carolina Republican, said he is also undecided about Trump's choice.
"I think probably what happened today is he is a good man, an honest guy, well qualified in terms of his life experience, but I don't think he grew the vote today," Graham said. "I think there are a lot of Democrats that may have been thinking about voting for him are going to have a harder time of it."
Graham said Tillerson failed to answer a key question at this hearing about what he intends to do about Russian election-related hacking.
"Real fuzzy answer," Graham said. "He needs to clear that up. If he doesn't clear that up, it would be a problem, and I think he can clear it up and he needs to clear it up."
Tillerson did get one small bit of good news - Sen. James Lankford, a Republican from Oklahoma, indicated on CNN's "Erin Burnett Out Front" that he is "leaning" toward a yes vote on Tillerson, but still wants to review more materials.
During his day-long testimony, Tillerson repeatedly broke with his future boss on key foreign policy issues, backing the Trans-Pacific Partnership, denouncing Russian aggression in Ukraine, and affirming his belief in climate change.
Tillerson said he wasn't against TPP, a massive trade pact that Trump condemned as he made staunch opposition to free trade deals a centerpiece of his presidential campaign.
"I do not oppose" TPP, Tillerson told the Senate Foreign Affairs Committee. "I share some of (Trump's) views regarding whether the agreement that was negotiated serves all of America's interests the best."
Tillerson also blasted Russia's invasion of Ukraine as an "illegal action" -- something Trump hasn't done -- and said he even would have sent the country defensive weapons to use against Moscow.
In a striking exchange, Tillerson admitted that he'd only spoken to the President-elect about world affairs in general terms, and that they haven't discussed Russian policy, telling the Senate panel "that has not yet occurred."
And he took steps in his opening remarks to strike an overall tougher line on Moscow than Trump has to date, saying, "Russia must know that we will be accountable to our commitments and those of our allies, and that Russia must be held to account for its actions."
On climate change, Tillerson told the senators he believes "the risk of climate change does exist and the consequences of it could be serious enough that actions should be taken." In contrast, Trump has in the past described climate change as a hoax perpetrated by China to hurt US manufacturers, although he recently acknowledged the possibility that human activity could be a contributing factor.
He expressed respect for Mexico, calling it "a longstanding neighbor and friend of this country." In sharp contrast to Trump, who said during the campaign that the country sends undocumented rapists and criminals to the US, Tillerson said, "I would never characterize an entire population by any single term at all."
And he distanced himself from calls to create a registry of American Muslims. "I do not support targeting any particular group," he said.
He also rejected Trump's campaign suggestion that South Korea and Japan should consider developing nuclear arsenals. "I do not agree," he said, adding, "We simply cannot back away from our commitment" to reduce nuclear weapons.
Tillerson encountered repeated challenges from senators on Russia and on ExxonMobil's track record on climate change and the company's opposition to sanctions against rogue regimes.
It was enough, at the hearing's halfway point, for Senate Democratic Leader Chuck Schumer of New York to tweet about the President-elect or "PEOTUS" and his State Department nominee.
"Tillerson hearing raises real questions as to whether PEOTUS & cabinet are prepared to stand up to Putin, Iran & represent US interests," Schumer said.
In a departure from the pattern, Tillerson noted his position on the nuclear deal with Iran was consistent with Trump's. He told senators that while "no one disagrees with the ultimate objective" to stop Iran from getting a nuclear weapon, he feels there should be a "full review of that agreement as well as any number of side agreements that are part of that agreement."
And he echoed Trump's frequent condemnations of China, calling Beijing's attempts to control airspace and its territorial claims "illegal actions." He said China's construction of artificial islands to further its territorial claims were "akin to Russia's taking of Crimea. It's taking of territory that others lay claim to."
Tillerson, who said he hadn't received any classified briefings on the alleged Russian hacks, agreed that it's a "fair assumption" that Putin authorized the attacks.
For weeks, Trump has denied or played down Moscow's involvement in efforts to meddle in the US election, although Wednesday, at a press conference Wednesday, Trump said, "I think it was Russia."
At the hearing, Democrats -- and some Republicans -- came out swinging.
Democrats questioned why in his prepared opening remarks Tillerson didn't mention Russia's alleged hacking of US elections, and they hammered his views on human rights and ExxonMobil's ties to Russia.
Trump's nominees and their confirmation hearings
Vice President Mike Pence, right, administers the oath of office to Dan Coats, the new director of national intelligence, on Thursday, March 16. Coats was accompanied by his wife, Marsha. He was confirmed by the Senate the day before.
Coats speaks on Capitol Hill before his confirmation hearing in February.
The former US senator from Indiana was the US ambassador to Germany in the first term of George W. Bush's administration.
New Energy Secretary Rick Perry speaks at his swearing-in ceremony in Washington on Thursday, March 2. The former Texas governor
was confirmed by a Senate vote of 62-37.
Perry is sworn in before his confirmation hearing in January.
During his testimony, Perry cast himself as an advocate for a range of energy sources, noting that he presided over the nation's leading energy-producing state. He also said he regrets once calling for the Energy Department's elimination.
Ben Carson is joined by his wife, Candy, and his granddaughter Tesora as he is sworn in as the secretary of housing and urban development on March 2. The renowned neurosurgeon and former presidential candidate
was confirmed by a vote of 58-41.
Carson greets Tesora prior to testifying before the Senate Committee of Banking, Housing and Urban Affairs in January.
In his opening statement, he noted that he was raised by a single mother who had a "third-grade education" and made the case that he understands the issues facing the millions of people who rely on HUD programs.
New Interior Secretary Ryan Zinke signs an official document after he was
confirmed by the Senate on Wednesday, March 1. The former congressman from Montana was joined by his wife, Lolita, as well as Vice President Mike Pence, US Sen. Steve Daines and Montana Attorney General Tim Fox.
Zinke, a former Navy SEAL, is sworn in before
his confirmation hearing in January. He pledged to review Obama administration actions that limit oil and gas drilling in Alaska, and he said he does not believe climate change is a hoax.
Pence swears in new Commerce Secretary Wilbur Ross as Ross' wife, Hilary, stands by on Tuesday, February 28. The billionaire
was confirmed by the Senate by a vote of 72-27.
Ross, center, waits to be introduced by US Sen. Marco Rubio, right, at his confirmation hearing in January. At the hearing, Ross said he wants countries that resort to "malicious" trading tactics to be "severely" punished. He
pointed the finger at China, which he called "the most protectionist country of very large countries."
Supreme Court justice Samuel Alito swears in Scott Pruitt as the new administrator of the Environmental Protection Agency on Friday, February 17. Holding the Bible is Pruitt's wife, Marlyn, and they were joined by their son, Cade. Pruitt, the former attorney general of Oklahoma,
was confirmed by the Senate 52-46.
Pruitt testifies at
his confirmation hearing in January. Pruitt said he doesn't believe climate change is a hoax, but he didn't indicate he would take swift action to address environmental issues that may contribute to climate change. He said there is still debate over how to respond.
Pence shakes hands with Mick Mulvaney after swearing him in as the new director of the Office of Management and Budget on Thursday, February 16. Mulvaney's wife, Pam, looks on. Mulvaney had been a congressman since 2011.
Mulvaney testifies before the Senate Budget Committee in January. He
didn't back off his views that entitlement programs need revamping to survive -- and he didn't back away from some of his past statements on the matter. President Donald Trump, during his campaign, pledged not to touch Social Security or Medicare.
McMahon speaks during her confirmation hearing. She stepped down from her WWE duties in 2009 and ran for the Senate in 2010 and 2012.
Pence watches David Shulkin, the new secretary of the Veterans Affairs Department, speak at his swearing-in ceremony on February 14. Shulkin was confirmed by
a unanimous vote in the Senate.
Shulkin speaks at his confirmation hearing. He was
the VA's undersecretary for health, a position in which he oversaw more than 1,700 health care sites across the United States.
Mnuchin arrives for his confirmation hearing in January. Mnuchin, a former Goldman Sachs banker,
faced policy questions about taxes, the debt ceiling and banking regulation.
Pence shakes hands with Health and Human Services Secretary Tom Price -- who was accompanied by his wife, Betty -- after a swearing-in ceremony on Friday, February 10. Price, a former congressman from Georgia,
was confirmed 52-47 in a middle-of-the-night vote along party lines.
Price testifies at his confirmation hearing in January. Price
confronted accusations of investing in companies related to his legislative work in Congress -- and in some cases, repealing financial benefits from those investments. Price firmly denied any wrongdoing and insisted that he has taken steps to avoid any conflicts of interests.
Trump watches as Pence administers the oath of office to Attorney General Jeff Sessions in the White House Oval Office on Thursday, February 9. Sessions, one of Trump's closest advisers and his earliest supporter in the Senate, was confirmed
by a 52-47 vote that was mostly along party lines. He was accompanied to the swearing-in by his wife, Mary.
In his
wide-ranging confirmation hearing, Sessions pledged to recuse himself from all investigations involving Hillary Clinton based on inflammatory comments he made during a "contentious" campaign season. He also defended his views of the Supreme Court's Roe v. Wade ruling on abortion, saying he doesn't agree with it but would respect it.
Pence swears in Education Secretary Betsy DeVos next to her husband, Dick, on Tuesday, February 7. Pence
cast a historic tie-breaking vote to confirm DeVos after the Senate was divided 50-50.
DeVos, a top Republican donor and school-choice activist,
prepares to testify at her confirmation hearing in January. DeVos
stood firm in her long-held beliefs that parents -- not the government -- should be able to choose where to send children to school, pledging to push voucher programs if she was confirmed.
Trump watches as Pence swears in Rex Tillerson as secretary of state on Wednesday, February 1. Tillerson's wife, Renda St. Clair, holds the Bible. Tillerson, a former CEO of ExxonMobil, was
confirmed in the Senate by a vote of 56 to 43.
Elaine Chao, Trump's pick for transportation secretary, signs the affidavit of appointment during her swearing-in ceremony in Washington on Tuesday, January 31. Chao is joined, from left, by Pence; her father, James Chao; and her husband, Senate Majority Leader Mitch McConnell.
Chao testifies at
her confirmation hearing in January. Chao, who was approved by a 93-6 vote, was deputy secretary of transportation under George H.W. Bush and labor secretary under George W. Bush.
South Carolina Gov. Nikki Haley takes the oath of office as she becomes the US Ambassador to the United Nations on Wednesday, January 25. She is joined by US Sen. Marco Rubio and staffer Rebecca Schimsa as she is sworn in by the vice president.
During her confirmation hearing, Haley rapped the UN for its treatment of Israel and indicated that she thinks the US should reconsider its contribution of 22% of the annual budget. "The UN and its specialized agencies have had numerous successes," Haley said. "However, any honest assessment also finds an institution that is often at odds with American national interests and American taxpayers. ... I will take an outsider's look at the institution."
Mike Pompeo is joined by his wife, Susan, as he is sworn in as CIA director on Monday, January 23. Pompeo, who is vacating his seat in the US House, was
confirmed by the Senate in a 66-32 vote.
Pompeo is sworn in at
his confirmation hearing. Along with Russia, Pompeo said other global threats include Iran's growing influence in the Middle East, ISIS' grip over major urban areas, and the conflict in Syria.
Mattis testifies before the Senate Armed Services Committee. He
emerged from his confirmation hearing with broad support after he took a strong posture against Russian President Vladimir Putin and answered tough questions on women and gays in combat.
Retired Marine Gen. John Kelly signs his confirmation letter on January 20. He is joined by his wife, Karen.
Kelly testifies
at his hearing. He was previously the head of US Southern Command, which is responsible for all military activities in South America and Central America.
Rubio started out by probing Tillerson's views on Russia's violations of human rights and its alleged war crimes in Syria, pointing to information in the public record about civilians being targeted in the Syrian city.
"Is Vladimir Putin a war criminal?" Rubio demanded.
"I would not use that term," Tillerson said. "Those are very, very serious charges to make, and I would want to have much more information before reaching a conclusion."
Sen. Robert Menendez, a New Jersey Democrat, challenged Tillerson on whether his business experience prepares him to represent the US to the world. "Diplomacy is not the same as deal making," Menendez said.
He also cited ExxonMobil's membership in a group that lobbied against Iran sanctions and Exxon's pursuit of a deal in Iraqi Kurdistan despite US opposition. And he brought into the hearing room documents showing millions in dollars of Exxon spending against sanctions on Iran and Russia.
"What message are you now going to be able to send to American businesses who are intent on pursuing their own interests at the expense of US policies and potential political stability in foreign countries," the New Jersey senator asked.
"I have never lobbied against sanctions, personally," Tillerson said. "To my knowledge, Exxon never directly lobbied against sanctions. Not to my knowledge."
"There was lobbying here," Menendez told him. "It's a little amazing that you don't know Exxon was lobbying on these issues."
In transition: President-elect Trump
President-elect Donald Trump shakes hands with Martin Luther King III
after they met at Trump Tower in New York on Monday, January 16. Afterward, King said the meeting was "constructive" and that the two discussed the importance of voting accessibility. Trump didn't speak to the media about the meeting.
Trump speaks at Trump Tower in New York on Wednesday, January 11. In
his first news conference since winning the election, a combative Trump made clear he will not mute his style when he is inaugurated on January 20. He lashed out at media and political foes alike.
US Sen. Jeff Sessions, Trump's nominee for attorney general, is sworn in during
his confirmation hearing in Washington on Tuesday, January 10. Trump and his transition team are in the process of filling high-level positions for the new administration.
Jared Kushner, Trump's son-in-law, arrives on Capitol Hill for a meeting with House Speaker Paul Ryan on Monday, January 9. Kushner, a 35-year-old businessman-turned-political strategist,
will be senior adviser to the president, a senior transition official told CNN.
Trump gets on an elevator after speaking with reporters at New York's Trump Tower on January 9.
Trump stands with Alibaba Executive Chairman Jack Ma, Asia's richest man, as they walk to speak with reporters at Trump Tower on January 9. Ma met with Trump to
tease plans for creating "one million" jobs in the United States. Trump praised Ma after the meeting as a "great, great entrepreneur and one of the best in the world."
Trump stands with legendary boxing promoter Don King after meeting at Trump's Mar-a-Lago resort in Palm Beach, Florida, on Wednesday, December 28. Trump and King
met to discuss the relationship between Israel and the United States.
Trump attends a meeting with Steve Bannon, chief White House strategist and senior counselor, at his Mar-a-Lago resort on Wednesday, December 21. Trump
spent the holidays in Mar-a-Lago.
Trump spokeswoman Kellyanne Conway talks to the press in the lobby of Trump Tower in New York on Thursday, December 15. Conway, who was Trump's campaign manager,
will work in his administration as "counselor to the president," it was announced on Thursday, December 22.
Trump
meets with technology executives in New York on Wednesday, December 14. From left are Jeff Bezos, chief executive officer of Amazon; Larry Page, chief executive officer of Google's parent company Alphabet; Sheryl Sandberg, chief operating officer of Facebook; and Vice President-elect Mike Pence. The three main areas discussed were jobs, immigration and China, according to a source briefed on the meeting.
Three of Trump's children -- from left, Donald Jr., Ivanka and Eric -- attend the meeting with tech leaders on December 14.
Trump, Pence and House Speaker Paul Ryan wave during an event in West Allis, Wisconsin, on Tuesday, December 13. "He's like a fine wine," Trump said of Ryan at
the rally, which was part of his "thank you" tour to states that helped him win the election. "Every day that goes by, I get to appreciate his genius more and more."
Trump and rapper Kanye West speak to the press after
meeting at Trump Tower in New York on December 13. Trump called West a "good man" and told journalists that they have been "friends for a long time." West later tweeted that he met with Trump to discuss "multicultural issues."
Trump
selected former Texas Gov. Rick Perry, right, to be his nominee for energy secretary, which would make Perry the head of an agency he once suggested he would eliminate.
Trump has tapped ExxonMobil CEO Rex Tillerson
to serve as secretary of state, the transition team announced December 13. Tillerson, seen here at a conference in 2015, has no formal foreign-policy experience, but he has built close relationships with many world leaders by closing massive deals across Eurasia and the Middle East on behalf of the world's largest energy company.
Trump waves during the Army-Navy football game, which was played in Baltimore on Saturday, December 10.
Trump shakes hands with Iowa Gov. Terry Branstad at an event in Des Moines, Iowa, on Thursday, December 8. Trump
re-introduced Branstad as his pick for US ambassador to China.
Trump greets retired Marine Gen. James Mattis at a rally in Fayetteville, North Carolina, on Tuesday, December 6. Trump said
he would nominate Mattis as his defense secretary.
Trump speaks to members of the media at Trump Tower in New York on December 6.
Trump visits the Carrier air-conditioning company in Indianapolis on Thursday, December 1.
Carrier announced that it had reached a deal with Trump and Vice President-elect Mike Pence, who is currently governor of Indiana, to keep about 1,000 of 1,400 jobs at its Indianapolis plant rather than move them to Mexico. The Carrier plant had been a theme of Trump's campaign promise to prevent more jobs from being outsourced to other countries.
Trump and former Massachusetts Gov. Mitt Romney
share a meal in New York on Tuesday, November 29. Romney was reportedly in the running for secretary of state.
Trump waves to a crowd at The New York Times building after meeting with some of the newspaper's reporters, editors and columnists on Tuesday, November 22.
Six takeaways from the meeting
Trump is flanked by Pence and Romney after a meeting in Bedminster Township, New Jersey, on Saturday, November 19.
"60 Minutes" correspondent Lesley Stahl
interviews Trump and his family at his New York home on Friday, November 11. It was Trump's first television interview since the election.
House Speaker Paul Ryan shows Trump and his wife, Melania, the Speaker's Balcony at the US Capitol on Thursday, November 10.
Trump walks with his wife and Senate Majority Leader Mitch McConnell after a meeting at the US Capitol on November 10.
Trump shakes hands with President Barack Obama following
a meeting in the Oval Office on November 10. Obama told his successor that he wanted him to succeed and would do everything he could to ensure a smooth transition.
Trump delivers his acceptance speech during his election night event at the New York Hilton Midtown hotel on Wednesday, November 9.
Maryland Democratic Sen. Ben Cardin later put into the record documents showing Exxon had spent $3.4 million lobbying against the Iran Sanctions Act.
Tillerson also tangled with Virginia Democratic Sen. Tim Kaine over long-standing allegations that ExxonMobil misled the public and its investors about internal research that outlined the threat of climate change. The company's shareholders have filed a class action lawsuit against the company in Texas, and it faces a similar lawsuit in Massachusetts as well.
"Do you lack the knowledge to answer my question or are you refusing to answer my question?" Kaine challenged the nominee.
"A little of both," Tillerson said.
CNN's Elise Labott and Matt Egan contributed to this report.