Washington • Our nation faces a constitutional conflagration, and President Trump is not the only actor willing to put personal and partisan interests above the preservation of our system of self-rule.

Five conservative justices on the United States Supreme Court signaled clearly on Tuesday that they are willing to allow the administration to act lawlessly in distorting the 2020 Census and thus representation in Congress to benefit the party that placed them on the court.

Trump’s brazen attacks on American institutions and the court’s partisanship are not separate stories. They are the product of a radicalization of American conservatism. Republicans and conservative ideologues — including the ones wearing the robes of justice — are destabilizing our institutions in pursuit of power.

The apparent willingness of the court's five conservatives to go along with the Trump administration on the census is of a piece with earlier rulings gutting the Voting Rights Act and increasing the power of big money in politics. All tilt the workings of our democratic republic in favor of conservative candidates, conservative causes and the appointment of conservative judges just like them.

At stake in Tuesday's court argument is Commerce Secretary Wilbur Ross' move to add a question to the 2020 census asking if a respondent is a citizen. Never mind that Ross lied about why he was including the question. Never mind that three lower courts ruled Ross' actions illegal. Never mind that the Commerce Department's own experts say this will lead many noncitizens to avoid answering the census, which means, according to one well-grounded estimate, it will miss 6.5 million people. Never mind that this would undercount places with large numbers of immigrants that tend to be Democratic and lead to skewed legislative representation.

Too bad, said conservative justices, whose hypocrisy was transparent. Chief Justice John Roberts, who had no problem eviscerating the Voting Rights Act, piously asked, "Do you think it wouldn't help voting rights enforcement?" Conservative justices regularly denounce using foreign law in our court decisions. This time, Justice Neil Gorsuch cited "evidence of practice around the world" to defend Ross' question, while Justice Brett Kavanaugh cited a United Nations recommendation.

When it comes to the president, his indifference to the law is so recurrent that we treat it almost as background noise. But we cannot become deaf to the message he is sending: He will destroy our constitutional arrangements if doing so will help him survive.

The House of Representatives is part of a coequal branch of our government with a responsibility to hold the executive branch accountable. In pursuit of this duty, the House regularly calls on administration officials to testify before its committees and to provide documents relevant to its work. There is always give-and-take in the process, but past administrations of both parties have acknowledged Congress' right to do its job.

Not Trump. He has issued a blanket diktat opposing testimony to Congress by current and former officials of his administration about the findings of special counsel Robert Mueller's investigation. He is also stalling or seeking to block the release of documents ranging from his income-tax returns to his business records. And he has made clear he does not view the House as having a legitimate, constitutionally sanctioned role in exploring what Mueller found for one simple reason: A body controlled by Democrats has no standing to question him.

"There is no reason to go any further, and especially in Congress where it's very partisan — obviously very partisan," he told The Washington Post.

Think about it: Only an autocrat says that when voters entrust part of the government to the party that's not his own, he will override its rights and prerogatives by fiat.

Ah, you say, but there are the courts. Trump can't possibly sustain his position, can he? Surely a judge is, as former Justice John Paul Stevens wrote, "an impartial guardian of the rule of law."

After Tuesday's arguments on the census, we can no longer have confidence that this is true.

It should thus come as no surprise that Trump tweeted on Wednesday morning: "If the partisan Dems ever tried to Impeach, I would first head to the U.S. Supreme Court."

Once upon a time, we could depend on justices regardless of party to stand up to a paranoid, power-mad president making weirdly unprecedented claims about the Supreme Court's role in the impeachment process. It should scare us, really scare us, that members of the court's conservative majority are giving us reason to wonder if they would do so now.

E.J. Dionne

E.J. Dionne writes about politics in a twice-weekly column for The Washington Post. He is a government professor at Georgetown University, a senior fellow in governance studies at the Brookings Institution and a frequent commentator on politics for National Public Radio and MSNBC. He is most recently a co-author of “One Nation After Trump.”