A familiar complaint, from exasperated liberals, over the first three and a half months of the Trump regime has been something on the order of, “When are the Republicans going to show some spine/grow a pair and stop this fool?”

The easy, glib answer is, “Probably never.”

The slightly less glib response is, “As soon as he puts their reelection in peril.”

And the third, somewhat more nuanced rejoinder is, “When they detect his base has abandoned him and it’s obvious they’re not going to get the ‘tax reform’ by which they are judged with him around.”

Watching (way too much) cable news last night and this morning, I had to snort at every pundit’s appeal to “principled conservatives” and “Republicans or honor” to stand up — now, in the immediate waking of Trump firing FBI Director Jim Comey — and demand an independent prosecutor to follow the Russia-Trump connections wherever they lead. Judging by Mitch McConnell’s statement this morning, that “immediate” thing ain’t gonna happen.

McConnell is the single best barometer of adult Republican/cynical electoral calculation. As long as old wattle-necked Mitch supports Trump, you know he doesn’t see an election-day upside to abandoning him to an independent anything. McConnell knows as well as other prominent Republicans that their hold on House and Senate majorities depends very heavily on the Trump base, and that base isn’t close to admitting they’ve been played for chumps (yet again) and are starting to bail on the guy they sent to D.C. to roll a hand grenade into every bureaucracy in town, including the FBI.

But … Mitch is going to have to start selling “Still Support Trump” a lot more aggressively than he has. Saturday Night Massacre comparisons aside, fury over the Comey firing is only going to build over the next few days and weeks. (It’ll build even faster if Comey makes his scheduled appearance before the Senate Intelligence Committee on Thursday. And faster still if various vows to haul in Deputy Attorney General Rod Rosenstein bear fruit. Rosenstein being the guy Trump says did the real dirty work in the Comey firing.)

Comey’s firing, added to the reignited rage over last week’s “TrumpCare” vote in the House, will suck a tremendous amount of attention and energy out of the push to do what Republicans always want to do most, namely accommodate their donor class with tax relief, I mean “reform”.

Point being, “tax reform” has just been pushed even further off toward the horizon. So fa off that old Mitch and other GOP “wise men” (entirely ironic description there) have to start wondering anew at how much better off they’d be with Mike Pence in the Oval Office … well before the clock flips over to 2018.

My personal fascination at the moment is with Rosenstein, a guy torn from obscurity to the harshest imaginable spotlight in barely a month. White House spox Sarah Huckabee Sanders didn’t even attempt to play coy this morning asserting flatly that it was Rosenstein who was responsible for every facet of the Comey firing, from recommending it to Trump to concocting a rationale to signing his name to the historical document.

It was breathtaking.

So … you gotta wonder how Rosenstein, allegedly a straight shooting ex-prosecutor, likes being picked up and heaved under the bus before he’s even figured out where the supply closet is in his own new office? If it were me, I’d be pissed as hell, to use the parlance of our times.

As I understand it, Rosenstein has the authority — today — to call for an independent prosecutor. Why he consented to ginning up the rationale for firing Comey is beyond me. The only explanation is that he is yet another DC careerist terrified he’d be fired if he refused, which makes me exceedingly skeptical that’ll he’ll man up now and go the special prosecutor route.

If he is another bureaucratic worm, his flaccid resolve might be stiffened a bit by GOP heavyweights like John McCain, Lindsey Graham and Richard Burr going well beyond “concerned” and “troubled” statements and demanding an independent investigation.

My guess though is that the Republican “wise men” need to see some thorough polling of the braying, foot-stompin’ Trump rally crowd before they go out on TV and get all righteous about, you know, defending the Constitution.