This environment has created constituencies that get less attention than the “with the president even if he shoots someone on Fifth Avenue” sort of Trump voter, but probably matter more to how impeachment plays out. These are voters who dislike Trump but give him some grudging credit for the solid economy and the absence of new foreign wars, voters who don’t support his policies but don’t share the educated-liberal revulsion at his style, and voters whose reluctant support is contingent on Trumpian chaos seeming confined to Washington.

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It’s possible to persuade these lukewarm voters to turn on him; you can see it begin to happen in the polling data when his party pursues unpopular policies (the Obamacare repeal push) or when his personal chaos seems to produce a real political breakdown (the government shutdown) or when his bigotry seems linked to some real-world horror (as with Charlottesville). But when a feeling of stability returns, when there isn’t a cascade toward economic debacle, foreign-policy catastrophe or late-1960s civil strife, these voters drift back toward mixed feelings, lukewarm support, dislike leavened by skepticism about removing Trump via impeachment rather than the 2020 vote.

Which is why, to return to the initial hypothesis, it mattered that the impeachment debate began at the same time that Trump was stumbling badly on foreign policy with Turkey and the Kurds; it gave some of these voters (and the swing-state Republican senators who represent them) a feeling that maybe this time everything was going to fall apart at once, that Trump’s incompetence would blow up the Middle East at the same time that his scandals multiplied.

Then the pattern in polling since — the dip in his approval rating giving way to a tiny upswing, support for impeachment peaking and then declining just a bit — might not reflect some dramatic failure by Democrats to make the case or some dramatic success for the Trumpian defense. Instead, it might just reflect the fact that the situation in Syria seems to have temporarily stabilized, the economy is fine and there are voters who will support removing a president when the world seems to be falling apart, but if it’s not, then not.

This reality doesn’t make a case against impeaching Trump when his conduct is basically asking for it; an impeachment process can be morally correct even if it’s unlikely to succeed. Nor does it prove that impeachment will hurt the Democrats in 2020; it might be that keeping a focus on Trump’s misdeeds and corruptions is a better use of Democratic energy than fighting over which not-necessarily-popular progressive agenda item their presidential nominee should be pressured to support.

Rather, it just makes a case for a certain modesty in all analysis, whether it’s a critique of some Adam Schiff stratagem today or a condemnation of Susan Collins (or, perhaps, Joe Manchin and Kyrsten Sinema) for not voting to remove the president tomorrow. It might just be the case that in our system it takes a clear cascade of disasters to pre-emptively remove a president, even a manifestly corrupt one. And though the likelihood of such a disaster the longer Trump remains in office is one reason to wish for his removal, even his fiercest critics should prefer stability, and the necessity of defeating him at the ballot box, to the Something Worse that might expedite his fall.