The New York Times editorial board’s opposition to President Donald Trump is well known. But on Monday, the paper devoted its entire editorial page to an unusually lengthy argument that “the president is not above the law,” calling on Congress to prepare for the possibility of Trump shutting down special counsel Robert Mueller’s investigation.

“Make no mistake: If Mr. Trump takes such drastic action, it will be striking at the foundation of the American government, attempting to set a precedent that a president, alone among American citizens, is above the law,” the editorial board wrote. “What can seem now like a political sideshow will instantly become a constitutional crisis, and history will come calling.”

Speculation that Trump might fire Mueller, Deputy Attorney General Rod Rosenstein, or Attorney General Jeff Sessions, or make some other attempt to shutter the Russia investigation, has built in recent weeks. The president is reportedly raging over the matter in private and, increasingly, in public, especially after the FBI raided his personal attorney Michael Cohen’s home and office last week.

Former FBI Director James Comey’s upcoming book and anti-Trump media blitz have further irked the president. He lashed out at Comey over the weekend on Twitter and has persistently attacked the Justice Department and the FBI. “Much of the bad blood with Russia is caused by the Fake & Corrupt Russia Investigation, headed up by the all Democrat loyalists, or people that worked for Obama,” Trump tweeted last week. “Mueller is most conflicted of all (except Rosenstein who signed FISA & Comey letter). No Collusion, so they go crazy!”

Much of the bad blood with Russia is caused by the Fake & Corrupt Russia Investigation, headed up by the all Democrat loyalists, or people that worked for Obama. Mueller is most conflicted of all (except Rosenstein who signed FISA & Comey letter). No Collusion, so they go crazy! — Donald J. Trump (@realDonaldTrump) April 11, 2018

The Times editorial on Monday warned that if Trump does indeed fire Mueller — which he has reportedly considered at least twice — the onus will be on Congress to step in. “Lawmakers need to be preparing now for that possibility because if and when it comes to pass, they will suddenly find themselves on the edge of an abyss, with the Constitution in their hands,” the editorial board wrote.

Editorials are written by a newspaper’s board and represent the official institutional position of the paper. It’s unusual for one to be this long and pointed. Editorials are different from op-eds, which are opinion pieces written by contributors and reflect the opinions of the individual author.

The editorial board takes aim at Sen. Orrin Hatch (R-UT), the former Judiciary Committee chair and current Finance Committee chair, who is now serving his seventh term in the Senate. It quotes Hatch discussing President Bill Clinton’s impeachment in 1999. “This great nation can tolerate a president who makes mistakes,” he said at the time. “But it cannot tolerate one who makes a mistake and then breaks the law to cover it up.”

The Times writes:

At that time, the American system — and the flawed yet sometimes heroic people their fellow Americans choose to lead them — underwent, and passed, a hard test: The president, his financial dealings and his personal relationships were painstakingly investigated for years. Prosecutors ultimately accused Mr. Clinton of lying under oath, to cover up a sexual affair. The House of Representatives impeached him, but the Senate declined to convict, and Mr. Clinton stayed in office. The public, which learned in detail about everything investigators believed Mr. Clinton had done wrong, overwhelmingly agreed with the judgment of the Senate. It was a sad and sordid and at times distracting business, but the system worked. Now Mr. Hatch and his fellow lawmakers may be approaching a harsher and more consequential test. We quote his words not to level some sort of accusation of hypocrisy, but to remind us all of what is at stake.

Last week, a bipartisan group of four Judiciary Committee senators — Thom Tillis (R-NC), Lindsey Graham (R-SC), Chris Coons (D-DE), and Cory Booker (D-NJ) — introduced a bill to protect Mueller from interference by Trump. The legislation would allow for Mueller or another special counsel to be fired only for “good cause” and allow special counsels to challenge their firing after the fact.

Tillis, in an interview with Politico published on Monday, pushed back against conservative critics of his decision to sponsor such a bill. “The same people who would criticize me for filing this bill would be absolutely angry if I wasn’t pounding the table for this bill if we were dealing with Hillary Clinton,” he argued. “So spare me your righteous indignation.”

Monday’s Times editorial presses Congress to get ready in the event Trump does decide to act on Mueller: