Washington(CNN) Hillary Clinton attacked Donald Trump as inexperienced. Trump called Clinton a failed foreign policy leader.
So began the homestretch to Election Day, as both candidates on Tuesday put national security squarely at the center of the 2016 campaign in the belief that it gives them the advantage.
Trump began by unveiling a list of 88 retired military leaders endorsing his candidacy, including four four-star generals and 14 three-star flag officers.
Then, alongside retired Lt. Gen. Michael Flynn at an event in Virginia Beach -- where fighter jets could be heard whooshing overhead -- Trump said of Clinton that "virtually every decision she's made has been a loser."
Russian President Vladimir Putin "looks at Hillary Clinton and he smiles," Trump said. "Boy, would he like to see her ... Because just look at her decisions. Look how bad her decisions have been."
In a split-screen moment, Clinton took the stage at the same time in Tampa to launch her own barrage of attacks.
Clinton dismisses calls for another congressional probe
"We are going to work with our allies, not insult them. We are going to stand up to our adversaries, not cozy up to them. We are going to have real plans, not claims and secret plans," said the former secretary of state.
Trump argued later Tuesday during a rally that Clinton's email use and her handling of classified information is "disqualifying."
"People who have nothing to hide don't smash phones with hammers. People who have nothing to hide don't bleach -- nobody's even ever heard of it -- their emails, or destroy evidence to keep it from being publicly archived as required under federal law," Trump said, pointing to Clinton aides' use of a software named BleachBit to expunge traces of deleted emails.
The security back-and-forth comes as the campaign enters its final two months and reminders of terror poised to return to the surface in advance of the 15th anniversary of the 9/11 attacks on Sunday.
A new CNN/ORC poll found that both candidates have advantages on national security. Those surveyed said they trust Trump more on terrorism (51% to Clinton's 45%), underscoring his ability to connect with the fears of Americans in an age of ISIS-inspired domestic attacks. But Clinton holds an edge on foreign policy (56% to Trump's 40%), enabling her to point to a wider range of national security credentials.
Dead heat
Overall, the poll showed the two candidates in a statistical dead heat, with Trump leading nationally among likely voters, 45% to Clinton's 43%.
Poll: Nine weeks out, a near even race
For Trump and Clinton, Tuesday's security focus came in two Southern swing states -- Virginia and Florida -- with large populations of veterans and military families.
Hillary Clinton's life in the spotlight
Hillary Clinton accepts the Democratic Party's nomination for president at the Democratic National Convention in Philadelphia on July 28, 2016. The former first lady, U.S. senator and secretary of state was the first woman to lead the presidential ticket of a major political party.
Before marrying Bill Clinton, she was Hillary Rodham. Here she attends Wellesley College in Massachusetts. Her commencement speech at Wellesley's graduation ceremony in 1969 attracted national attention. After graduating, she attended Yale Law School.
Rodham was a lawyer on the House Judiciary Committee, whose work led to impeachment charges against President Richard Nixon in 1974.
In 1975, Rodham married Bill Clinton, whom she met at Yale Law School. He became the governor of Arkansas in 1978. In 1980, the couple had a daughter, Chelsea.
Arkansas' first lady, now using the name Hillary Rodham Clinton, wears her inaugural ball gown in 1985.
The Clintons celebrate Bill's inauguration in Little Rock, Arkansas, in 1991. He was governor from 1983 to 1992, when he was elected President.
Bill Clinton comforts his wife on the set of "60 Minutes" after a stage light broke loose from the ceiling and knocked her down in January 1992.
In June 1992, Clinton uses a sewing machine designed to eliminate back and wrist strain. She had just given a speech at a convention of the International Ladies' Garment Workers Union.
During the 1992 presidential campaign, Clinton jokes with her husband's running mate, Al Gore, and Gore's wife, Tipper, aboard a campaign bus.
Clinton accompanies her husband as he takes the oath of office in January 1993.
The Clintons share a laugh on Capitol Hill in 1993.
Clinton unveils the renovated Blue Room of the White House in 1995.
Clinton waves to the media in January 1996 as she arrives for an appearance before a grand jury in Washington. The first lady was subpoenaed to testify as a witness in the investigation of the Whitewater land deal in Arkansas. The Clintons' business investment was investigated, but ultimately they were cleared of any wrongdoing.
The Clintons hug as Bill is sworn in for a second term as President.
The first lady holds up a Grammy Award, which she won for her audiobook "It Takes a Village" in 1997.
The Clintons dance on a beach in the U.S. Virgin Islands in January 1998. Later that month, Bill Clinton was accused of having a sexual relationship with former White House intern Monica Lewinsky.
Clinton looks on as her husband discusses the Monica Lewinsky scandal in the Roosevelt Room of the White House on January 26, 1998. Clinton declared, "I did not have sexual relations with that woman." In August of that year, Clinton testified before a grand jury and admitted to having "inappropriate intimate contact" with Lewinsky, but he said it did not constitute sexual relations because they had not had intercourse. He was impeached in December on charges of perjury and obstruction of justice.
The first family walks with their dog, Buddy, as they leave the White House for a vacation in August 1998.
President Clinton makes a statement at the White House in December 1998, thanking members of Congress who voted against his impeachment. The Senate trial ended with an acquittal in February 1999.
Clinton announces in February 2000 that she will seek the U.S. Senate seat in New York. She was elected later that year.
Clinton makes her first appearance on the Senate Environment and Natural Resources Committee.
Sen. Clinton comforts Maren Sarkarat, a woman who lost her husband in the September 11 terrorist attacks, during a ground-zero memorial in October 2001.
Clinton holds up her book "Living History" before a signing in Auburn Hills, Michigan, in 2003.
Clinton and another presidential hopeful, U.S. Sen. Barack Obama, applaud at the start of a Democratic debate in 2007.
Obama and Clinton talk on the plane on their way to a rally in Unity, New Hampshire, in June 2008. She had recently ended her presidential campaign and endorsed Obama.
Obama is flanked by Clinton and Vice President-elect Joe Biden at a news conference in Chicago in December 2008. He had designated Clinton to be his secretary of state.
Clinton, as secretary of state, greets Russian Prime Minister Vladimir Putin during a meeting just outside Moscow in March 2010.
The Clintons pose on the day of Chelsea's wedding to Marc Mezvinsky in July 2010.
In this photo provided by the White House, Obama, Clinton, Biden and other members of the national security team receive an update on the mission against Osama bin Laden in May 2011.
Clinton checks her Blackberry inside a military plane after leaving Malta in October 2011. In 2015, The New York Times reported that Clinton exclusively used a personal email account during her time as secretary of state. The account, fed through its own server, raises security and preservation concerns. Clinton later said she used a private domain out of "convenience," but admits in retrospect "it would have been better" to use multiple emails.
Clinton arrives for a group photo before a forum with the Gulf Cooperation Council in March 2012. The forum was held in Riyadh, Saudi Arabia.
Obama and Clinton bow during the transfer-of-remains ceremony marking the return of four Americans, including U.S. Ambassador Christopher Stevens, who were killed in Benghazi, Libya, in September 2012.
Clinton ducks after a woman threw a shoe at her while she was delivering remarks at a recycling trade conference in Las Vegas in 2014.
Clinton, now running for President again, performs with Jimmy Fallon during a "Tonight Show" skit in September 2015.
Clinton testifies about the Benghazi attack during a House committee meeting in October 2015. "I would imagine I have thought more about what happened than all of you put together," she said during the 11-hour hearing. "I have lost more sleep than all of you put together. I have been wracking my brain about what more could have been done or should have been done." Months earlier, Clinton had acknowledged a "systemic breakdown" as cited by an Accountability Review Board, and she said that her department was taking additional steps to increase security at U.S. diplomatic facilities.
U.S. Sen. Bernie Sanders shares a lighthearted moment with Clinton during a Democratic presidential debate in October 2015. It came after Sanders gave his take on the Clinton email scandal. "The American people are sick and tired of hearing about the damn emails," Sanders said. "Enough of the emails. Let's talk about the real issues facing the United States of America."
Clinton is reflected in a teleprompter during a campaign rally in Alexandria, Virginia, in October 2015.
Clinton walks on her stage with her family after winning the New York primary in April.
After Clinton became the Democratic Party's presumptive nominee, this photo was posted to her official Twitter account. "To every little girl who dreams big: Yes, you can be anything you want -- even president," Clinton said. "Tonight is for you."
Obama hugs Clinton after he gave a speech at the Democratic National Convention in Philadelphia. The president said Clinton was ready to be commander in chief. "For four years, I had a front-row seat to her intelligence, her judgment and her discipline," he said, referring to her stint as his secretary of state.
Clinton arrives at a 9/11 commemoration ceremony in New York on September 11. Clinton, who was diagnosed with pneumonia two days before, left early after feeling ill. A video
appeared to show her stumble as Secret Service agents helped her into a van.
Clinton addresses a campaign rally in Cleveland on November 6, two days before Election Day. She went on to lose Ohio -- and the election -- to her Republican opponent, Donald Trump.
After conceding the presidency to Trump in a phone call earlier,
Clinton addresses supporters and campaign workers in New York on Wednesday, November 9. Her defeat marked a stunning end to a campaign that appeared poised to make her the first woman elected US president.
Clinton aides, who asked for anonymity while talking about strategy, said the focus on national security is part of a confluence of important dates and forums with Trump.
Early voting, which includes mail-in ballots traditionally used by active-duty military, begins in many states this month. In some states, like Florida, active-duty military are asked to send in ballots starting in late September and early October.
Another factor is that Trump has given her material to work with, Clinton aides said. They described her as relishing going after Trump on this topic because she feels she knows it well and he doesn't. It also allows her to target Republican-leaning voters who have been turned off by Trump.
"His whole campaign has been one long insult to all those who have worn the uniform," Clinton said on Tuesday in Tampa, just miles from MacDill Air Force Base, where 15,000 people work.
Clinton's push also comes with another prize in mind: "Security moms," or female voters who are concerned about terrorism -- particularly middle-class suburban women in must-win swing states like Pennsylvania.
A late-August Franklin and Marshall poll found Clinton ahead by 15 points in Southeastern Pennsylvania -- largely Philadelphia's suburbs -- even as the Republican incumbent senator leads his Democratic challenger by 9 points in the same region. That margin would be close to insurmountable for Trump on Election Day.
Clinton, press do awkward dance at 30,000 feet
"Any viable path for him would require mitigating that damage somewhat," said Hari Sevugan, a former Obama campaign spokesman who's now a strategist for the Democratic firm 270 Strategies.
Sevugan said timing is also at play, though the focus on national security isn't driven solely by the approaching September 11 anniversary.
"People are starting to tune in and focus in a more concentrated way on the election after Labor Day, and it makes sense from the Clinton perspective to really home in on where they have a relative strength," Sevugan said. "And from the Trump perspective, they need to shore this up."
But Bryce Reeves, a Republican candidate for lieutenant governor of Virginia in 2017 and a former Army Ranger, said national security is a concern across all demographic groups -- and one that can give a big boost to Trump.
"It's a matter of time" before another terror attack, he said. "It's not a matter of it we get hit, it's a matter of when we get hit and how we respond to those threats. ... That's why you're seeing a renewed interest by the candidates."
Clinton: Trump 'choked' when meeting with Mexican president
He said the release of Trump's military endorsements earlier Tuesday underscores the qualifications of the people he'd listen to as president.
"The sign of a great leader is to surround yourself with phenomenal people, and if you look at Trump's record today -- who he put out supporting him -- he's got numerous flag officers who led troops in the field during some of our most heightened recent conflicts," Reeves said.
National security focus
National security will be a focus all week. Clinton and Trump will participate in a joint forum Wednesday sponsored by the Iraq and Afghanistan Veterans of America and broadcast on NBC and MSNBC -- their first joint appearance of the campaign.
Clinton is also bolstering her national security push with a new television ad called "Sacrifice," highlighting Trump's criticism of Arizona Sen. John McCain's war-hero status and his fight with the Muslim parents of an American soldier killed in combat.
Donald Trump's rise
President-elect Donald Trump has been in the spotlight for years. From developing real estate and producing and starring in TV shows, he became a celebrity long before winning the White House.
Trump at age 4. He was born in 1946 to Fred and Mary Trump in New York City. His father was a real estate developer.
Trump, left, in a family photo. He was the second-youngest of five children.
Trump, center, stands at attention during his senior year at the New York Military Academy in 1964.
Trump, center, wears a baseball uniform at the New York Military Academy in 1964. After he graduated from the boarding school, he went to college. He started at Fordham University before transferring and later graduating from the Wharton School, the University of Pennsylvania's business school.
Trump stands with Alfred Eisenpreis, New York's economic development administrator, in 1976 while they look at a sketch of a new 1,400-room renovation project of the Commodore Hotel. After graduating college in 1968, Trump worked with his father on developments in Queens and Brooklyn before purchasing or building multiple properties in New York and Atlantic City, New Jersey. Those properties included Trump Tower in New York and Trump Plaza and multiple casinos in Atlantic City.
Trump attends an event to mark the start of construction of the New York Convention Center in 1979.
Trump wears a hard hat at the Trump Tower construction site in New York in 1980.
Trump was married to Ivana Zelnicek Trump from 1977 to 1990, when they divorced. They had three children together: Donald Jr., Ivanka and Eric.
The Trump family, circa 1986.
Trump uses his personal helicopter to get around New York in 1987.
Trump stands in the atrium of the Trump Tower.
Trump attends the opening of his new Atlantic City casino, the Taj Mahal, in 1989.
Trump signs his second book, "Trump: Surviving at the Top," in 1990. Trump
has published at least 16 other books, including "The Art of the Deal" and "The America We Deserve."
Trump and singer Michael Jackson pose for a photo before traveling to visit Ryan White, a young child with AIDS, in 1990.
Trump dips his second wife, Marla Maples, after the couple married in a private ceremony in New York in December 1993. The couple divorced in 1999 and had one daughter together, Tiffany.
Trump putts a golf ball in his New York office in 1998.
An advertisement for the television show "The Apprentice" hangs at Trump Tower in 2004. The show launched in January of that year. In January 2008, the show returned as "Celebrity Apprentice."
A 12-inch talking Trump doll is on display at a toy store in New York in September 2004.
Trump attends a news conference in 2005 that announced the establishment of Trump University. From 2005 until it closed in 2010, Trump University had about 10,000 people sign up for a program that promised success in real estate.
Three separate lawsuits -- two class-action suits filed in California and one filed by New York's attorney general -- argued that the program was mired in fraud and deception. Trump's camp rejected the suits' claims as "baseless." And Trump has charged that the New York case against him is politically motivated.
Trump attends the U.S. Open tennis tournament with his third wife, Melania Knauss-Trump, and their son, Barron, in 2006. Trump and Knauss married in 2005.
Trump wrestles with "Stone Cold" Steve Austin at WrestleMania in 2007. Trump has close ties with the WWE and its CEO, Vince McMahon.
For "The Apprentice," Trump was honored with a star on the Hollywood Walk of Fame in January 2007.
Trump appears on the set of "The Celebrity Apprentice" with two of his children -- Donald Jr. and Ivanka -- in 2009.
Trump poses with Miss Universe contestants in 2011. Trump had been executive producer of the Miss Universe, Miss USA and Miss Teen USA pageants since 1996.
In 2012, Trump announces his endorsement of Republican presidential candidate Mitt Romney.
Trump speaks in Sarasota, Florida, after accepting the Statesman of the Year Award at the Sarasota GOP dinner in August 2012. It was shortly before the Republican National Convention in nearby Tampa.
Trump appears on stage with singer Nick Jonas and television personality Giuliana Rancic during the 2013 Miss USA pageant.
Trump -- flanked by U.S. Sens. Marco Rubio, left, and Ted Cruz -- speaks during a CNN debate in Miami on March 10. Trump dominated the GOP primaries and emerged as the presumptive nominee in May.
The Trump family poses for a photo in New York in April.
Trump speaks during a campaign event in Evansville, Indiana, on April 28. After Trump won the Indiana primary, his last two competitors dropped out of the GOP race.
Trump delivers a speech at the Republican National Convention in July, accepting the party's nomination for President. "I have had a truly great life in business," he said. "But now, my sole and exclusive mission is to go to work for our country -- to go to work for you. It's time to deliver a victory for the American people."
Trump apologizes in a video, posted to his Twitter account in October, for vulgar and sexually aggressive remarks he made a decade ago regarding women. "I said it, I was wrong and I apologize,"
Trump said, referring to lewd comments he made during a previously unaired taping of "Access Hollywood." Multiple Republican leaders rescinded their endorsements of Trump after the footage was released.
Trump walks on stage with his family after he was declared the election winner on November 9. "Ours was not a campaign, but rather, an incredible and great movement," he told his supporters in New York.
Trump is joined by his family as he is sworn in as President on January 20.
And her super PAC, Priorities USA, is launching a $5 million ad buy in the swing states North Carolina, Ohio, Florida, Nevada, Iowa and New Hampshire on Friday with a spot titled "I Love War."
Featuring a mushroom cloud, it touts Trump's hawkish remarks about war and nuclear weapons.
Meanwhile, Clinton's running mate, Tim Kaine, delivered a security-focused speech Tuesday in Wilmington, North Carolina, accusing Trump of flip-flopping on how the United States should handle the war in Iraq.
"He says whatever he feels like at any given time because you can do that when you're a TV star. But you can't do that when you're president of the United States," Kaine said.
Trump and Clinton themselves also fought Tuesday over remarks Trump had made in an interview that aired on ABC's "Good Morning America."
"I just don't think she has a presidential look and you need a presidential look," Trump said of Clinton.
"I'm talking about general, by the way, she says things about me that are horrible," Trump said. "As an example the single greatest asset I have, according to those that know me, is my temperament."
Clinton's camp seized on the comments, using them to highlight Trump's previous fights with the Gold Star Khan family, his criticism of Fox News host Megyn Kelly and his questioning of President Barack Obama's birthplace.
"This isn't the first time Donald Trump has had a problem looking at someone different from himself and actually seeing them," said Clinton deputy communications director Christina Reynolds.
Clinton also continued to fight back criticism of her use of a private email server as secretary of state.
She shrugged off calls for additional congressional inquiries into her email usage as nothing more than pandering to right-wing conspiracy theorists, suggesting that the FBI "resolved" all the questions into her email use during their investigation.
Clinton, speaking with her traveling press corps aboard her new campaign plane on Tuesday, said she has "just accepted" the fact that Republicans will continue to call for investigations into her, whether they are warranted or not.
Clinton added, "I believe I have created so many jobs in the, sort of, conspiracy-theory machine factory. Because, honestly, they never quit. They keep coming back."
CNN's Dan Merica and Jeremy Diamond contributed to this report