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Susan Collins is an increasingly rare species. It’s not just that she’s a moderate Republican, or a northeastern Republican, or even a pro-choice Republican. It’s that she still believes in the honor system in Washington.

Justice Anthony Kennedy’s retirement at the end of last month’s term has ignited heated political maneuvering over his replacement. President Trump is expected to announce his nominee to fill Kennedy’s Supreme Court seat on Monday, and it will test whether Collins’s faith is justified or shows itself to be as outdated and fragile as the many other norms discarded during the Trump era. Because the Republican margin in the Senate is slim and because she is a moderate, pro-choice member, the Maine senator has quickly become the center of speculation about the fate of Trump’s nominee. If Democrats maintain a united front, which is never a sure thing, Collins could be the swing vote, determining whether a nominee makes it to the bench or goes the way of Robert Bork.

“I would not support a nominee who demonstrated hostility to Roe v. Wade, because that would mean to me that their judicial philosophy did not include a respect for established decisions, established law,” Collins told CNN’s Jake Tapper on Sunday.

She told ABC’s Martha Raddatz much the same. “So a nominee’s position, whether or not they respect precedent, will tell me a lot about whether or not they would overturn Roe v. Wade,” Collins said. “A candidate of this important position who would overturn Roe v. Wade would not be acceptable to me, because that would indicate an activist agenda that I don’t want to see a judge have.”

Collins also said she asked the president to expand his list of possible nominees beyond a previously released list. However, the three leading contenders for the seat are all on Trump’s list: Brett Kavanaugh, a judge on the D.C. Circuit Court of Appeals; Raymond Kethledge, a member of the Sixth Circuit Court; and Amy Coney Barrett, who sits on the Seventh Circuit.

By Wednesday, Collins was becoming a little peevish (by restrained Susan Collins standards) about the questions she was getting about the Court seat.

“I think I’ve made it pretty clear that if a nominee has demonstrated hostility to Roe v. Wade and has said they’re not going to abide by that long-standing precedent, that I could not support the nominee, but we don’t even know who the nominee is,” she told NBC News. “What I’m telling you is, how can you ask me to take a position on a nominee whose identity I don’t yet know?”

Collins’s frustration is understandable. But her description of her test for a nominee remains nebulous—and, for those who worry about Roe’s future, not especially reassuring. The problem is that no smart, ambitious conservative judge will take a clear stand on Roe if he or she can possibly avoid it, and no judge is likely to say publicly that he or she doesn’t respect precedent.

Collins says it “would be inappropriate to ask a judge nominee on how they are going to vote in a future case.” Most judges won’t answer questions like that anyway, at least not publicly. This creates an awkward dance during the confirmation process, as senators try to extract pledges that nominees will uphold their preferred stances, and judges try to avoid being pinned down on anything, both to bolster their chances at confirmation and to preserve their flexibility on the bench.

Long before they are nominated, upwardly mobile conservative jurists try to avoid a “demonstrated hostility” toward Roe, because they know that if they want to make it to the Supreme Court, they’re going to have to get past people like Susan Collins. This extends to many issues beyond abortion. In recent decades, Supreme Court nominations have become more and more partisan, and presidents have increasingly sought to appoint young justices to the bench, in order to mark the Court with their ideology for as long as possible. As a result, aspiring justices have sought to leave as short a paper trail as possible about their views on hot-button issues, and their comparative youth means they’ve had less time to create liabilities.

Trump has said publicly he didn’t plan to ask prospective nominees about Roe, and Collins told Raddatz he privately told her the same. Nonetheless, the president has been clear that he wants to see Roe overturned. “If we put another two or perhaps three justices on, that's really what’s going to be—that will happen,” he said during the final 2016 presidential debate. “And that’ll happen automatically, in my opinion, because I am putting pro-life justices on the Court. I will say this: It will go back to the states, and the states will then make a determination.” This week, Aaron Blake of The Washington Post notes, Trump reprised those comments in an interview with Fox News, again saying it should be up to states—a euphemism for overturning Roe.

Of the three reported finalists, Barrett has been most explicit about Roe, writing in a 2003 article that Roe was an “erroneous decision.” But even that can be explained away, which points to the second prong of Collins’s test: respect for precedent. Barrett is hardly alone in her critique of Roe, and objections to the decision exist among progressives, too. Even the liberal lion Ruth Bader Ginsburg, a supporter of abortion rights, has critiqued Roe’s methods. If nominated, Barrett could, and perhaps will, say that while she disagrees with the reasoning in the decision, she also respects the precedent.

Just as no aspiring justice will say he or she opposes Roe outright, neither will a judge say he or she doesn’t respect precedent. Nonetheless, the Supreme Court does overturn precedents from time to time. Last month, the Supreme Court case Janus v. AFSCME undermined the financing of public-sector unions, effectively reversing a 1977 decision, Abood v. Detroit Board of Education. The case split along partisan lines, with the five GOP-appointed judges voting with the majority and the four Democrat-appointed judges dissenting. In her dissent, Justice Kagan bitterly complained about the reversal of the earlier decision. “The majority has overruled Abood for no exceptional or special reason, but because it never liked the decision,” she wrote. “It has overruled Abood because it wanted to.”

It will come as little surprise that all five of the justices who voted with the majority endorsed the importance of following precedent, often referred to as the doctrine of stare decisis, during their confirmation hearings. Here’s Samuel Alito, who wrote for the majority in Janus:

I think the doctrine of stare decisis is a very important doctrine. It’s a fundamental part of our legal system, and it’s the principle that courts in general should follow their past precedents, and it’s important for a variety of reasons.

Chief Justice John Roberts:

Judges have to have the humility to recognize that they operate within a system of precedent shaped by other judges equally striving to live up to the judicial oath, the importance of settled expectations in the application of stare decisis is a very important consideration.

Clarence Thomas:

Senator, I think that the principle of stare decisis, the concept of stare decisis is an important link in our system of deciding cases in our system of judicial jurisprudence.

Neil Gorsuch:

A good judge starts with precedent and doesn’t reinvent the wheel.

Interestingly, Kennedy was most tentative in his deference to precedent during his 1987 hearings, but he did say:

Stare decisis ensures impartiality. That is one of its principal uses. It ensures that from case to case, from judge to judge, from age to age, the law will have a stability that the people can understand and rely upon, that judges can understand and rely upon, and that attorneys can understand and rely upon. That is a very, very important part of the system.

None of these quotes are intended to show that the justices who voted in the majority in Janus are hypocrites. It merely shows that even justices who respect stare decisis in principle sometimes find occasion to overturn past decisions. And that means that Collins is unlikely to receive any assurance of respect for precedent that she can take to the bank. The senator’s office did not reply to a request for comment about how she plans to navigate the twin challenges of reticence about Roe and porous commitments to precedent.

Collins still subscribes to an increasingly rare if not entirely extinct way of doing things. She assumes that the people she’s doing business with are honorable and have good intentions, even when there is plenty of evidence to suggest otherwise. She is not a phony, but her fidelity to this outdated ethos does make her look like an easy mark. She publicly criticized Senate Majority Leader Mitch McConnell’s decision to roadblock Barack Obama’s nomination of Merrick Garland to the Supreme Court, but she was powerless to stop it. In 2017, she cut a deal with White House legislative-affairs director Marc Short, agreeing to vote for a Trump-backed tax bill on the condition that the Senate also vote on a bill to stabilize Obamacare markets. With Collins’s vote safely cast, the White House reneged on the deal.

Collins is willing to break with Trump, having voted against the confirmation of  former Environmental Protection Agency Administrator Scott Pruitt and Education Secretary Betsy DeVos. But she voted to confirm Gorsuch—who many analysts believe would join a majority to overturn Roe—and also voted in 2017 to confirm Barrett to the appeals court.

Combined, all of this history suggests Collins will vote for Trump’s pick (even though, as the senator would be quick to note, he or she has not been named). After all, the nominee is unlikely to condemn Roe or to disavow stare decisis. That will give Collins sanction to vote in favor, solving a short-term political dilemma, but very possibly setting up the demise of Roe that Collins says she wants to prevent. Perhaps that’s simply the kind of risk that a senator has to take when deciding whether to vote for powerful appointments.

If Collins does vote yes, and the eventual nominee turns out to defer to Roe’s precedent, it will show that there’s still some life and breath in the old ways. If, however, the new justice helps to overturn Roe, it will once again show how moribund the old honor system is. As Cervantes demonstrated some 400 years ago, there can be honor and poignancy in abiding by a defunct code of honor—it just isn’t very effective at getting what you want.

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