Something is going on with President Trump and Russia. But what, exactly, is a question that has loomed darkly over his entire presidency.

Then, on Tuesday evening, the Russia question exploded into a full-blown constitutional crisis, when the president abruptly and unceremoniously fired FBI Director James Comey. It was pretty obviously an abuse of power meant to hamstring the FBI's investigation into Trump's connections with Russia.

Comey's ouster sparked the usual Democratic calls, many of them full of perfunctory and performative outrage, for a congressional investigation and the appointment of a special prosecutor to finally get to the bottom of the Trump-Russia story. Let's get real. There is little chance that Republicans will seriously consider reining in Trump. It's a safe bet that Congress will do nothing about Trump's corruption so long as Republicans believe they can control it.

There is only one path to investigate and stop Trump: Democrats must win some elections.

Like everything Trump does, the act of firing Comey was so hamfisted it can hardly be believed. The stated justification for the firing was Comey's mishandling of Hillary Clinton's email investigation — which was terrible, no question. But setting aside the fact that Attorney General Jeff Sessions was instructed to come up with pretexts for axing Comey, and the firing came just after Comey had asked for additional resources for the Trump-Russia investigation, this justification is simply preposterous. No honest person can possibly believe that Donald "Lock Her Up" Trump — who effusively praised Comey for the email investigation in October — cares in the slightest about unfair treatment doled out to Clinton. And indeed, leaks immediately confirmed that the real motivation was anger at the ongoing Russia investigation.

Don't get me wrong: There's a strong case that Comey deserved to lose his job. (I argued six months ago that he ought to resign.) But the extraordinary rationale behind Trump axing the FBI director demands investigation, as do all the swirling questions surrounding Trump and Russia.

At first, there were some encouraging signs of resistance from a few congressional Republicans, notably including Senate Intelligence Committee chair Richard Burr. But they were few and far between. Democrats must assume that they will not hold Trump to account while Republicans are in charge. The only way to get Congress to fulfill its constitutional duty is for Democrats to take control.

Controlling even one house of Congress would give Democrats most of the tools they need to stymie Trump. The point of firing Comey was, pretty obviously, to stop the Russia investigation (or, in other words, "obstruction of justice"). Controlling Congress would give Democrats control of committees, the legislative calendar, the ability to hold hearings, subpoena power, and so forth. They could make the rest of Trump's presidency a nightmare of investigations and probes.

If Democrats controlled both houses, they could appoint a special select committee chosen from both chambers so as to represent the full weight of the legislature in confrontation with the executive. That would be ideal.

But the main point is to get to the bottom of Trump and Russia. Subpoena every relevant document, drag every relevant person before an investigative committee, and grill them mercilessly. This administration leaks like a sieve and is filled with feuding, backbiting idiots. It ought to be easy to get one or two people — Michael Flynn, or Paul Manafort, or Roger Stone, or one of dozens of others — to crack under the klieg lights, and from there to unravel the whole story. At this point, it is frankly ludicrous to think there isn't something there, be it electoral collusion or some business corruption.

If and when a smoking gun is found, Republicans might finally start to abandon Trump. If they don't, then it ought to be a tremendous political weapon against them in 2020, as it was for Democrats in 1976.

But Democrats' goals must be bigger than Trump himself. If they are to defuse the threat of Trumpism, and help cure the rot within the Republican Party, they must win not only in 2018 and 2020, but again and again and again — and use the power thus gained to cement their own grip on government and to restore civic health to the whole population.

To do this, Democrats must learn from the many mistakes in their recent past. In a piece tomorrow, I'll explain how. Stay tuned.