Brendan Smialowski / AP

The final weeks of November may be remembered as the moment when Donald Trump crushed the last vestiges of resistance to him in the Republican Party. The sole remaining question is whether that conquest extends to the Republican-appointed justices on the Supreme Court—especially the chief justice, John Roberts.

A stark confluence of events these past few weeks, from the House of Representatives to the Pentagon, has underscored how thoroughly Trump has broken almost all meaningful opposition within the GOP ranks. “There never was that much resistance, but I do think there has been some final capitulation of some of the semi-holdouts, or at least the ones who were keeping their distance,” says the longtime conservative strategist Bill Kristol, a leader of the Never Trump movement. “No one would have predicted the Republican Party would have been in this position” when Trump was initially elected.

The practical impact of this deference is to loosen constraints on Trump as he implements his virtually unlimited view of unilateral presidential power. One lesson of the Trump presidency is that one party alone, even if it controls a chamber of Congress, does not have enough leverage to stymie such a vision. Though the Democratic majority in the House eliminates Trump’s capacity to advance legislative goals, the past year has demonstrated that without support from the Republican Senate, the chamber has very limited ability to overturn Trump’s unilateral actions. Even the impact of a potential House vote to impeach would be blunted if few or no Republicans vote for it, and if GOP senators oppose removing Trump with comparable uniformity.

Such an outcome might actually embolden Trump to push further against the boundaries of law and convention, especially if he’s reelected in 2020. If Republicans will not vote to sanction him for his coercion of Ukraine—which has been painstakingly detailed in public testimony—many observers believe that he would justifiably question whether there is anything he could do that they would rebel against.

“If he gets reelected, all bets are off,” Kristol says. “Everything he’s done is legitimized. Pardoning war criminals, flouting congressional oversight—why would he just not assume he can get away with all of that, especially if Republicans continue to hold the Senate, which they would if he won. The second term is all this on steroids, and I think it’s a genuine crisis at that point.”

The clear signal from Washington is that any earlier Republican inclination to constrain Trump has severely frayed. On Capitol Hill, House Republicans—even those who are considered more independent of Trump, such as Will Hurd of Texas—uniformly defended or excused his pressure campaign on Ukraine during the House Intelligence Committee’s impeachment hearings, even to the point of belittling some of the career diplomats and military officials who testified. Representative Elise Stefanik of New York, who many Trump-skeptical conservatives once believed could help define an alternative vision for the party, instead used the hearings to position herself as one of his most ferocious defenders.

“The theory of the party that I had had three years ago, which was that people like Elise Stefanik and Will Hurd were going to become the new face of the Republican Party, has been shown to be conclusively wrong,” says Geoffrey Kabaservice, the director of political studies at the libertarian Niskanen Center.

Within the executive branch, Trump once faced at least some internal resistance from figures such as Chief of Staff John Kelly, Defense Secretary James Mattis, and, in his own way, Attorney General Jeff Sessions. These days, little seems to be left. There’s extensive evidence that Secretary of State Mike Pompeo, despite the concerns of career officials, participated in Trump’s maneuvers to force Ukraine to investigate former Vice President Joe Biden, Trump’s potential opponent in 2020. And Attorney General William Barr has stripped away any veneer of the Justice Department’s traditional distance from the White House: He’s advanced arguments that assert virtually complete immunity for Trump from congressional or law-enforcement investigations, and he launched an inquiry into the original FBI probe of Russian influence on the 2016 Trump campaign, traveling the world to pressure foreign governments to participate in it.

There’s little defiance even beyond matters of impeachment. Defense Secretary Mark Esper willingly dismissed Navy Secretary Richard Spencer earlier this month after Spencer resisted Trump’s orders to circumvent the military-justice system in a high-profile war-crimes case. The recent declarations by GOP leaders that Trump’s election was ordained by God capture the (extreme) extent to which he has molded the party to his will. “No one is trying to stand up to him,” says Kabaservice, the author of Rule and Ruin, a history of the struggles between conservatives and moderates in the GOP.

With congressional Republicans and executive-branch officials malleable to Trump’s demands, the most practical constraint on his actions may be the courts. Yet they look like a fragile barrier as well.

Across a wide array of issues, Trump has suffered several reversals at the district- and appellate-court levels. But for the biggest questions, all legal roads lead to the same place: a Supreme Court divided between five justices appointed by Republican presidents and four appointed by Democrats.

Kabaservice says he’s cautiously optimistic that the courts, including the Supreme Court, will limit Trump’s assertions of almost unlimited executive-branch power. Most judges appointed by Republican presidents, he argues, have traditionally been leery of excessive federal authority of any sort, and support the separation of powers as a means to check government overreach. Prominent conservative scholars who claim almost unfettered presidential authority—such as John Yoo, a law professor at UC Berkeley and a former attorney in the George W. Bush administration—are the exception, he believes.

“Most of the people who have come up [as Republican court appointees] would tend toward a Reaganite view of limited federal [authority] … rather than a Trumpian view of unlimited executive power,” he says.

But many other analysts say that, in practice, Republican appointees on the courts—particularly the Supreme Court—have already shown enormous deference to Trump’s claims of expansive authority. In 2018, the five Republican-appointed Supreme Court justices outvoted the others to uphold Trump’s ban on travel from mostly Muslim nations, for example. In more recent questioning, the same coalition appeared poised to allow Trump to end President Barack Obama’s Deferred Action for Childhood Arrivals program, which sheltered from deportation young people brought to the country illegally by their parents.

The biggest departure to this pattern of deference from the Court’s GOP majority came in June, when Roberts joined with the four Democratic appointees to block the administration’s effort to add a citizenship question to the 2020 census, which critics feared would depress minority participation.

Trump’s boundless instinct to press presidential boundaries virtually ensures that the Supreme Court will continue to face a steady flow of cases testing his claims. It already is facing cases involving Trump’s efforts to prevent both congressional investigators and New York criminal investigators from obtaining his tax returns, and his claims of “absolute immunity” from congressional testimony for current and former close aides appear headed toward the Court, too.

All this means that whether Trump stays in office for one more year or five, one of the key variables will be whether Roberts’s ruling in the census case was an exception or a signal of his determination to limit presidential authority. Most observers consider it unlikely that any of the four other Republican-appointed justices—including Trump’s two nominees—will break from the president on many, if any, big cases.

Jessica Levinson, a professor at Loyola Law School, in Los Angeles, who closely tracks the Supreme Court, says Roberts’s history signals that the census case is more likely to be the exception than the rule. While that case involved particularly egregious facts that undermined the administration’s justification for its actions, Roberts has far more often expressed support for broad executive authority of the sort Trump is asserting, she says. Asked how much of an impediment she expects Roberts to pose, she said, “Based on his public comments and his writings in other previous cases, I think the indication is not that much.”

The one countervailing force, Levinson and other experts noted, is Roberts’s reluctance to have the Court viewed as simply another extension of the partisan conflict between Republicans and Democrats. His attempt to avoid that characterization led Roberts to publicly rebuke Trump last summer for insisting that there are “Obama judges” and “Trump judges.”

But that consideration was not enough to dissuade Roberts from participating in other five-four party-line decisions that have dealt with Trump’s powers. “We are kidding ourselves that he is a moderate,” Levinson said. “Let’s none of us pretend that he doesn’t have a view of broad executive power.”

Still, Roberts could ultimately be the last man standing in the GOP with the ability to say no to a president who barrels through law and custom. Few questions may shape Trump’s remaining tenure more than how often Roberts steps into the breach.

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