As noted in a previous post, some too-clever Democratic strategists don’t want to talk about impeachment for fear of animating the Trump base to turn out and vote this November. But there are not enough hard-core Trumpers to keep the House in Republican hands.
Once Dems take back the House, impeachment inevitably becomes the first order of business. For several months—if Trump is still in the White House by next January—more of the lurid details of his corruption and opportunism will be spread across the public record as the Democratic House uses its full investigative powers. And the House is very likely to vote for impeachment.
This would then put Republican senators in an exquisite bind, heading into a presidential year: Back Trump to the end, alienate swing voters, and go down with the ship? Or vote to convict and infuriate the hard-core Trump base? Meanwhile, criminal prosecutions for Trump's close associates and family are coming down the pike.
One way or another, Trump is likely to be gone by the 2020 presidential election. One possibility is that Trump, ever the deal-maker, cuts a grand deal with the impeachers and the prosecutors: He resigns the presidency, in exchange for no prosecutions. That way, he saves his skin and his brand. That deal could also look better and better to Senate Republicans, who don't share their House counterparts' enthusiasm for Trump.
There is no parallel to the disgrace of the current Republican Party in putting opportunistic ideological and legislative gains ahead of the Republic. The legislative orgy will be over after this November, and Republicans will be looking to their own futures in the face of more and more hard evidence of Trump's thuggery and a rising Blue Tide.