Those fearful that an impeachment drive would mobilize his base should consider how Trump already keeps his supporters in a constant state of political mobilization through demagoguery and fear-mongering. Instead of thinking about their opponents, Democrats should focus on their supporters, who voted in large numbers to give the party a House majority and keep the president in check. Even if Democrats won’t commit to an impeachment vote, an expressed willingness to consider an impeachment inquiry could help activate those voters and keep them energized through the next year and a half.

There’s also little reason to worry about a backlash that helps the president. Donald Trump is not Bill Clinton, who was unusually popular from 1997 onward, with a second-term job approval average of 61 percent. Even accounting for political polarization, Trump is unusually unpopular, weighed down by constant scandal and chaos. As late as January of this year, a majority of voters — 53 percent, according to a poll from Quinnipiac — said that Trump is “not fit to be president.”

And high-profile coverage of the president’s scandals has an impact. In a Reuters poll that measured immediate reactions to the Mueller report, Trump’s approval rating declined to 37 percent. The same survey shows a slight increase in support for impeachment (40 percent versus 39 percent March) and a significant decrease in opposition to impeachment (42 percent say Trump should not be impeached versus 49 percent in March).

It’s possible that voters will change their minds in the face of an impeachment threat against the president. But given existing public opinion, it’s more likely that an impeachment investigation would deepen the sense that Trump is unfit for the office he holds.

The symbolic and the practical aside, there’s also the real question of our constitutional order. Either the president is above the law or he isn’t. Voters can’t determine this — elections aren’t actually the venue for adjudicating that kind of conflict. This is a job for our elected representatives in Congress. And if House Democrats believe Trump has violated the Constitution, they have an obligation to act on that belief, even if conviction in the Senate is impossible under current political circumstances. Elijah Cummings, the chairman of the House Oversight Committee, made this point on Sunday in an interview on “Face the Nation.” “Even if we did not win, possibly, if there were not impeachment, I think history would smile upon us for standing up for the Constitution,” he said.

The potential impossibility of conviction itself is an important message for the public to take in. Many Americans may still believe that sufficient wrongdoing would bring both parties together to remove a lawless president. If that isn’t true — if presidential accountability of this sort is impossible under divided government — then Americans deserve to know. Then, at least, we can have a national discussion about what that means for the Constitution.

Caution on impeachment makes sense. It is a monumental step that would shape politics in unforeseen and potentially negative ways. But inaction, or even just ordinary action, has risks too. Trump will continue try to shape the post-Mueller narrative to his advantage, condemning the investigation as a “witch hunt” from its origin to its conclusion. His allies will do the same. Even if they fail to persuade the public, they can muddy the waters and turn this constitutional conflict into another case of partisan bickering.

Democrats still have to defeat Trump at the ballot box, which means building a mass coalition against his politics. At worst, impeachment could crowd out the material case against Trump, centering the election on legal questions versus the impact of his presidency on people’s lives. But there’s another possibility: that impeachment helps Democrats make a truly comprehensive case against the president, uniting his corruption, his criminality and his contempt for ordinary Americans under a single narrative. Impeachment, pursued with vigor, then becomes part of the larger argument against him and the Republican Party that has bolstered his presidency, indifferent to its corrosive effect on all parts of American life.

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