Here's the key bit:

"Make no mistake: If Mr. Trump takes such drastic action, he 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. What can seem now like a political sideshow will instantly become a constitutional crisis, and history will come calling for Mr. [Orrin] Hatch and his colleagues."

The Times editorial makes the case that while people like Hatch, a Republican senator from Utah, as well as Republican Sens. Lindsey Graham of South Carolina and Chuck Grassley of Iowa, have spoken out about the consequences for Trump of firing either Rosenstein or Mueller, the broader Republican party has been largely silent.

"More Republicans need to make it clear that they won't tolerate any action against either man, and that firing Mr. Mueller would be, as Senator Charles Grassley said, 'suicide,'" says the Times op-ed.

The reason for that (relative) silence is simple: Republicans have zero interest in pissing off Trump (and his loyal base) for a hypothetical question about what they would do if he did fire either the special counsel or the guy who appointed the special counsel. Why engage about something that a) hasn't happened and b) may never happen? Cross that bridge when you come to it -- and all that.

The Times op-ed makes clear that sort of political maneuvering isn't good enough when you are talking about stakes as high as these. And, the piece devastatingly reminds us of just how many Republican members of Congress took shots at Trump -- " malignant clown ," " national disgrace, " " complete idiot, " " a sociopath , without a conscience or feelings of guilt, shame or remorse" -- before he was the party's presidential nominee.

Two somewhat contradictory things occur to me about this piece:

1. When the Times editorial board goes this big on a subject, it's going to get lots and lots of attention. Cable news will talk about it relentlessly. It will fuel discussions among partisans -- and among not-so-partisans -- for weeks and maybe months to come.

2. The piece will provide Trump with further fodder for his attacks on the "failing" Times and the media more generally -- attacks that his base will eat up. Trump will use the op-ed as evidence that the Times doesn't want him to be president and is urging people within his own party to get rid of him. (Worth noting: The Times editorial board is totally and completely distinct from the Times' reporters who cover Trump. My guess is the President and his allies won't note that distinction.)

Why do it then? No matter what you think of the Times, it's hard to imagine that they didn't know that this op-ed would draw an intensely negative reaction from Trump and his backers. And that it wouldn't change many minds -- on either side of the Trump equation.

To my mind, the op-ed is rightly read as a line in the sand. It's making clear that GOP members of Congress can't look back if/when Trump fires Rosenstein or Mueller and say they didn't see it coming or don't know what they should next. The Times is saying, essentially this: We are living in a historic and critical moment. What you do now -- and in the coming months -- matters. And the decisions you make will have long-lasting consequences. So don't just play politics with it.

The closing paragraph of the Times' editorial lays these stakes out plainly. It reads:

"The president is not a king but a citizen, deserving of the presumption of innocence and other protections, yet also vulnerable to lawful scrutiny. We hope Mr. Trump recognizes this. If he doesn't, how Republican lawmakers respond will shape the future not only of this presidency and of one of the country's great political parties, but of the American experiment itself."

It doesn't get much bigger than that.