(CNN) Two years ago, after a Supreme Court nomination divided the country, Chief Justice John Roberts recognized the need for repair and asserted judicial independence.
"We speak for the Constitution," Roberts said 10 days after the Senate confirmed Justice Brett Kavanaugh. "We do not serve one party or one interest. We serve one nation."
With Monday's confirmation of Amy Coney Barrett, Roberts will have a tougher case to make -- under thornier circumstances tied immediately to the presidential election and the Affordable Care Act.
Barrett's appointment, hurried through by President Donald Trump and Senate Republicans after last month's death of liberal Justice Ruth Bader Ginsburg, will give conservatives a new 6-3 dominance. Yet, Barrett, based on her record, could have even sharper consequences for the law in America. She represents a departure from Ginsburg, of course, but her narrow "originalist" approach to constitutional rights also separates her from Roberts, a 2005 appointee of President George W. Bush.
The court hovers on the brink of an historic transformation, on social dilemmas such as abortion rights, LGBTQ protections and the place of religion in public life, as well as regarding federal regulation for the environment, workplace safety and consumer protection.
Roberts had been at the exact ideological center of the court and was determining the outcome of just about every important case, including those over Trump administration policy and the President's bank and accounting records.
He provided a moderating influence, much to the consternation of Trump and hard-line conservatives. The 65-year-old chief appeared to be trying to prevent a crisis of legitimacy amid partisan attacks on the judiciary by Trump and escalating confirmation wars in the Senate.
Roberts will have less control now. The bench could ultimately be steered by the three Trump appointees, all of whom are considerably younger than Roberts -- Barrett by 17 years.
But if anyone can chart some path through today's politicized judiciary, it is Roberts. The former star appellate advocate has a pattern of finding a way out of high-profile dilemmas at the intersection of law and politics.
He has muted his conservative instincts in some areas of the law for institutional interests. He has slowed the pace of the most charged cases. The court has moved to the right during his 15-year tenure, to be sure, but he has tried to prevent a lunge.
Roberts may be able to persuade his colleagues on the right that such a course remains best for the court's reputation, especially if members of Congress accelerate their talk about expanding the number of seats on the high court to diminish the right-wing dominance.
On the conservative wing with Roberts, Kavanaugh and soon-to-be Justice Barrett, are Justices Clarence Thomas, Samuel Alito and Neil Gorsuch. On the left remain Justices Stephen Breyer, Sonia Sotomayor and Elena Kagan.
As chief justice, Roberts retains the power to assign opinions for the court when he is in the majority. So even with the pull of new weight on the far right, Roberts is apt to align with his conservative colleagues to control the legal rationale of a decision and the speed of change.
In sequences of difficult cases, Roberts has demonstrated a pattern of trying to offer something to each side. Even as he ruled against Trump administration policy, for example, on young undocumented immigrants known as "Dreamers" and the 2020 census, his legal reasoning favored executive branch interests and gave the administration a roadmap for a potential court win.
On voting rights, perhaps the most salient issue for the justices in this election season, Roberts has a solid conservative record but has inched to the left enough recently to shatter any predictions for the many emergency election disputes rushing toward the justices.
In one of the most defining decisions of his tenure, Roberts penned the 2013 Shelby County v. Holder case that eviscerated a crucial section of the 1965 Voting Rights Act requiring states with a history of discrimination to obtain federal approval for any new voter-identification rule or other electoral change. And in April, Roberts took the lead with conservatives to refuse to extend a deadline for absentee ballots in Wisconsin as the coronavirus pandemic was escalating.
Still, last week in a Pennsylvania case, Roberts joined the three liberals to leave in place a Pennsylvania court decision allowing mailed ballots to be received up to three days after Election Day.
In the minefield of cases the justices will consider in upcoming weeks -- tied to the election and new challenges to the Affordable Care Act and 2020 census practices -- Roberts might convince his colleagues that minimal action or a split outcome is best.
He may be able to persuade Barrett that it would be best not to "jolt" -- to use a word Roberts invoked during his own confirmation hearings -- the legal system and public expectations.
That would mean that the Affordable Care Act, to be before the justices on November 10, would not be struck down. The legal arguments for sinking it are weak and conflict with the plain intention of Congress. Under Roberts' leadership, the Supreme Court twice before, in 2012 and 2015, rejected arguments that would have driven a stake through Obamacare.
As a Notre Dame law professor before becoming a judge, Barrett criticized those decisions, particularly the 2012 case when Roberts cast the fifth vote, with four liberals, to uphold the ACA. He construed a disputed provision requiring Americans to purchase health insurance as part of Congress' taking power.
"Chief Justice Roberts pushed the Affordable Care Act beyond its plausible meaning to save the statute," Barrett wrote in a 2017 law review essay. When the high court rejected the second challenge, Barrett said in a radio interview that she thought dissenting justices had "the better of the legal argument."
The ACA, which Congress passed a decade ago, provided health coverage to 20 million more Americans; it expanded Medicaid, to low-income adults, allowed children to stay on their parents' policies until age 26 and prevented insurers from denying coverage to people based on pre-existing conditions such as cancer and diabetes.
In litigation related to the November 3 election, Roberts may try to avoid a ruling that directly affects the outcome of the presidential race between Trump and former Vice President Joe Biden.
Roberts is aware that the Bush v. Gore decision 20 years ago tarnished the court's reputation. Roberts, then in private practice, assisted the legal team of former Texas Gov. George W. Bush that ending up prevailing over Vice President Al Gore. Kavanaugh and Barrett also helped Bush's efforts at the time.
Kavanaugh, based on his recent record, may be the likeliest partner for Roberts in a centrist conservative position.
Kavanaugh joined the chief in a handful of cases over the past two years as Thomas, Alito and Gorsuch took a harder conservative stance, for example, as the court rejected a challenge to a New York firearms regulation earlier this year. Kavanaugh has also on occasion sided with Roberts to spurn a contentious appeal, such as in late 2018 when the court denied, over dissent from Thomas, Alito and Gorsuch, a petition from states that wanted to end their Medicaid financing of Planned Parenthood.
On the left, Kagan has taken the lead for cross-ideological consensus. Like Roberts, she has an ability to generate creative ways out of seemingly intractable dilemmas.
Kagan helped steer the majority's 2019 decision that blocked the Trump administration from adding a citizenship query to the 2020 census and navigated with Roberts and Gorsuch earlier this year for a six-justice consensus applying federal anti-bias law to gay and transgender workers.
Breyer, the only member of the current court to have been a top aide in Congress -- to Massachusetts Sen. Ted Kennedy in the 1970s -- has similar instincts for compromise. But with Ginsburg's death, the left side of the bench simply has less leverage than it has had for decades.
Ginsburg's death also makes the 82-year-old Breyer the eldest justice and the one most likely to consider retirement. If Biden wins the White House and Democrats similarly seize the Senate majority, Breyer may consider stepping down.
Such a Biden-appointed successor would not alter the ideological make-up of the bench. Yet the change would mark one more inflection point in a five-year period of Supreme Court volatility.
Justice Antonin Scalia's death in 2016 eventually led to the 2017 Gorsuch appointment, followed by Kavanaugh in 2018 and now Barrett.
This period of unpredictability contrasts with the one that began with Breyer's 1994 appointment. For 11 years, there was not one change among the nine justices.
Only in 2005, with the death of Chief Justice William Rehnquist, did a new member take his seat on the bench: Roberts, right in the center.
This story has been updated with Barrett's confirmation to the court.