When President Trump gleefully leapt to Twitter to revel in the firing of FBI Deputy DirectorAndrew McCabe, to observe that the Mueller investigation is a WITCH HUNT led by “hardened Democrats” (Robert S. Mueller III is a Republican), and to point out that the House investigation found no collusion (“Our committee was not charged with answering the collusion idea,” mumbled Rep. K. Michael Conaway (R-Tex.) on “Meet The Press“), it seemed as though he was contemplating the Heretofore Unthinkable Course of trying to shut down the Mueller investigation. His lawyer John Dowd even put forth a request that the investigation stop.

But there is no cause for alarm. Should the president attempt such a course, the Republicans who hold power in Congress have made it clear that they will … be disappointed.

One or two even have definite plans to compose a strongly worded letter to the president and think very, very hard about sending it. Another handful will go so far as to whisper to some reeds growing just on the edge of the great swamp that they think this idea is “very bad, and a travesty of our values.”

With one voice, Republicans in Congress have made it clear that if the president takes this extreme step, they will not be afraid to defy him by appearing on a cable news channel and saying something noncommittal. As they are doing right now. For instance, Sen. Lindsey O. Graham (R-S.C.) said on CNN’s “State of the Union,” “If he tried to do that [fire Mueller], that would be the beginning of the end of his presidency.” Beware, President Trump! If you continue down your present course, there is every reason to believe that Graham may even go so far as to write a memoir where he calls this “a dark, dark moment for this country, when people should have spoken up.”

Sen. Marco Rubio (R-Fla.) is likewise standing firm. If the president crosses this hardest, firmest red line, Rubio will be, like, super bummed, and probably also go on TV and say words to that effect, and maybe even deliver a speech that includes stinging phrases like “I weep for our democracy” — which would be delivered directly into a camera.

Senate Majority Leader Mitch McConnell (R-Ky.) has said nothing publicly, but those around him have been given to understand that if the president crosses this red line, McConnell will crumple up whatever paper he happens to be holding at the time and throw it to the ground and say, “Darn!” loudly.

Some Republicans have even spoken up already. House Speaker Paul D. Ryan (R-Wis.) said this weekend, through a spokesperson, that he continues to see firing Mueller as a red line, and that he is pretty sure that if the president crosses it, someone will stop him. (Someone brave, probably. Someone who was in a position to do something about this.) Rep. Trey Gowdy (R-S.C.) said he has confidence that we will get to hear the outcome of the Mueller investigation, because when have we ever seen this president violate norms in a surprising, disappointing way? Sen. Jeff Flake (R-Ariz.) said he is confident in the courage of his fellow Republicans, who have never let him down before, and that they will do the right thing regardless of the electoral consequences. (He is not running for reelection.) But just in case that does not work out, he is in New Hampshire right now shaking hands and kissing babies.

The red line is certainly not slowly receding into the distance like a mirage; it is definitely real, and it will kick in this time. People should not be worried: If the future of our democracy depends on the courage of the current crop of Republican lawmakers, we can rest assured that when the time comes, they will put country over party and eventually say something stern, as they open for Trump at a rally.

It is reassuring to hear the Republicans in the legislative branch, one of the checks and balances holding our democracy precariously in place, speaking in chorus that there are some breaches they will not enjoy accepting with only a murmur of protest. It will be grueling and disheartening for them to sit there silently and watch this unfold without taking the slightest action to stop it. They are not looking forward to it at all.