So now it's finally official. After five weeks of fact-finding behind the closed doors of the House Intelligence Committee, the full House of Representatives has now voted (along party lines, except for two Democrats who opposed the measure) to bring a full-fledged impeachment case against President Trump. What will follow is likely to be several weeks of public hearings and witness testimony followed by a vote on one or more articles of impeachment. If a majority votes in favor of at least one of them, a trial in the Senate will commence soon afterward, the outcome of which will be either acquittal of the president or his removal from office.

None of us knows for sure what the end result of the impeachment process will be. What we can know is that this is the last stand for the Republican Party as we knew it up until the 2016 election cycle.

Over and over again we've been told that the old guard and its high ideals has been defeated, vanquished, and humiliated by the Trump insurgency. And that's true to a considerable extent. It's true on policy, where the GOP's long-standing positions on international affairs, trade, and immigration have crumbled one by one, prompting fleeting bouts of grumbling but little beyond that. It's also true on even longer-standing conservative adherence to principles of constitutionalism, public rectitude, and the rule of law, which under Trump has become quite a bit more … selective than it once was.

Tying the party's fate to a trash-talking racist and misogynist who traffics in conspiracy theories, lies constantly, and displays greater affection for foreign autocrats than he does for members of the opposition party will do that.

But that doesn't mean every Republican in Washington is happy about it. They may have sold their souls in public, but many of them are consumed by disgust and self-loathing in private. That's one reason why so many Republican members of the House are lining up to retire — because the gonzo politics on display at last week's sham "protest" of House intelligence committee hearings on possible Trump law breaking and abuse of power, like today's garbage talk about how strictly adhering to constitutional procedures on impeachment amounts to following "Soviet-style rules," is motivated by a soulless craving for power at all costs. And not everyone is willing to say and do anything and everything for the sake of power.

The fact is that the Republican base, fed a diet of ideologically based conspiracies and malicious half-truths by talk radio and Fox News for decades, is furiously angry and deeply attached to their profane tribune in the Oval Office. It's also the case that lots of Republican House members represent districts that are safely in the GOP column. That creates a strong incentive for anyone who wants to remain in Washington to turn themselves into Trump minions and defenders — both to encourage constituents to vote and to prevent a primary challenge from the Trumpist right. That's what holding onto power now requires.

But the dynamic in the Senate is different. Yes, the threat of primary challenges is always there, too. But senators represent entire states. Some of them are safely red. But many others are filled with millions of Democrats and independents. The further right a senator moves and the more he or she embraces an obviously corrupt and deeply unpopular president, the more vulnerable he or she might become in a future general election campaign against a compelling Democrat.

If the case against Trump is thin — if independents end up unimpressed by the evidence presented against him by the Democrats — hardly any Republican senators (perhaps not even Mitt Romney) will vote to convict and remove the president. They'll claim what Trump did with Ukraine was bad, but not bad enough to justify use of the constitution's nuclear option.

But if the case is strong — if a series of credible, manifestly patriotic and law-abiding citizens portray the president as a lawless thug who considers it perfectly acceptable to strong-arm weak foreign governments into helping him cheat to keep power — and independents continue to be scandalized by the evidence, then all bets are off.

The idea that the Senate would remove an impeached president for the first time in American history when the president's own party holds the majority — and that this would happen in such a sharply polarized moment, when the president's own-party approval remains around 90 percent — seems fanciful. But that doesn't mean it won't happen or can't happen.

It could and it might. If it does, it will be because sufficient numbers of old-line, non-populist Republican senators come to see it as their last stand — their last opportunity to act as a force for the public good rather than an enabler of a criminal enterprise cheered on by a mob motivated by ignorance and malice.

Will the party fold, falling into line behind Trump, as it has so many times over the past four years? Probably. But it won't if its members recall that their job isn't to do whatever the voters demand regardless of whether it's reasonable. Their job is to listen to those demands and then do what they consider right and good for the country and the Constitution they've taken an oath to preserve, protect, and defend.

Republicans used to care about such things. We're about to find out if they still do.