Individual Republican congresspeople have seen what has happened to the political careers of people like Rep. Mark Sanford and Sens. Bob Corker and Jeff Flake who have tried to stand up to the president. They don’t want to be next. But, collectively, the party needs to have a strategy for how to deal with a rogue president who commits felonies and (as we saw in Helsinki) is clearly compromised by an adversarial foreign power. The problem is pretty simple to understand. While congressional Republicans are bound to their president, Republican voters are not. They can walk away from the party, leaving behind only strong Trump supporters.

In most of suburban America, this has already turned into a kind of Holocaust for country club Republicans. Fewer and fewer college educated professionals (especially women) are willing to self-identify as supporters of the GOP, and it’s not possible for Republican candidates to hold these seats based on fire-breathing opponents of immigration.

The very fact that Trump dominated the Republican primaries showed how marginalized college educated people have become in the Republican Party, but the process has only continued since Trump has been in office. The typical Trump supporter had complete disdain for all Trump’s establishmentarian rivals for the nomination, and that contempt extended (and extends) to the Republican leadership in Congress. They have never liked Mitch McConnell and they especially hate Paul Ryan for abandoning Trump after the Access Hollywood tape came out. They don’t support Republicans in Washington except in the very limited sense that they rely on them to protect the president and enact his agenda. This is why the Republicans want to use the threat of impeachment as a motivational tool, because Trump’s voters might turn out to deal with that threat but they’re not reliably going to turn out to support a congressperson or senator that they don’t even like.

From the Republicans’ perspective, accountability for the president isn’t a priority because Trump supporters do not care about his crimes, and they need Trump’s supporters to come out to vote in November. Even so, they realize that they have a big problem:

Republican strategist Josh Holmes, who advises Senate Majority Leader Mitch McConnell (R-Ky.), attempted to downplay the political cost of the convictions.

“I don’t think it’s the atomic bomb that others have suggested,” he said. “I don’t think anybody who is a Trump supporter has been sitting around for the past six months banking their support on the president’s denial of his relationship with Stormy Daniels.”

Holmes said he feared, though, that Trump could lose much-needed votes in suburban swing districts.

They hope the prospect of impeachment will help turnout, but they have a backup plan to mobilize Trump’s base.

Republican candidates are joining the White House’s campaign to offer public support for Immigration and Customs Enforcement (ICE), warn of the dangers of the Salvadoran MS-13 gang and highlight sensational crimes involving undocumented immigrants.

The aim is to draw a sharp contrast with Democrats over enforcement of border control laws. Republican strategists view immigration as a deeply emotional issue that motivates the conservative base, and they have delighted as liberals push Democrats to the left as a reaction to Trump’s presidency.

“It’s a galvanizing issue among the base,” said Josh Holmes, a top political adviser for Senate Majority Leader Mitch McConnell (R-Ky.), who previously served as his chief of staff. “The Democrats have increasingly migrated to a place on this issue far from where your everyday American is. The contrast is mind-boggling.”

The Democrats’ strategists aren’t stupid. They understand the Republicans’ two-part strategy for boosting turnout and they’re wary about doing their job for them. That’s why they’re tamping down talk of impeachment and discouraging talk about abolishing ICE. They also realize that the Republican donor base is largely satisfied with Trump’s policies and will stick with him up to a point. Of course, they’d be just as happy with Mike Pence, so Trump shouldn’t bank on their loyalty if things get truly dicey.

Of course, if the Democrats don’t show enough principle and fight, they may depress their own turnout, but it does seem sensible to take a wait-and-see approach to any discussion of impeachment. There is no harm in waiting for the evidence before making sweeping promises to the voters.

The one thing I don’t think is helpful is to continuously talk about how the Republicans in the Senate will never convict Trump even if the House impeaches him with the support of the American people. They will certainly be reluctant to do so for all the reasons I’ve already suggested, but it will really come down to the facts of the case.

If Trump is proven to have actively coordinated with the Russians despite all his denials, and if the people who were responsible for this are willing to attest to what they did, then Mike Pence is going to look like a very attractive option. To be honest, Pence is much better liked and a better ideological fit for congressional Republicans than Trump.  The reason they stick with Trump is because their own ineptitude weakened them so much that Trump was able to take over their party, and now they can’t win without his supporters.  They’re caught in a vice.

In the end, after they’ve taken their losses despite sticking with Trump, the remaining senators are not going to be eager to go into 2020 with Trump as their champion.  Since they don’t like or trust him anyway, if they can’t win with or without him, it’ll be far preferable to lose without him. There is a limit to how much shit they will eat to defend a man like Trump, and if the evidence comes in and it’s strong enough, there will be enough Republican senators who will choose removal over arguing that Trump should remain in office despite having done what he was accused of doing and then lying about it for two years.

Of course, they still won’t want to have to vote on it, so they’ll do what Barry Goldwater did in 1974 and go tell the president that he should resign.

All of this, of course, depends on the strength of the evidence. If close coordination with the Russians isn’t proved then there is almost no limit to how many crimes and outrages Trump can commit without worrying that the Senate will convict him. The GOP proves this anew almost every single day, including in their reaction to the Manafort and Cohen stories.