Second, impeachment has energized Trump’s base. According to Gallup, the president’s approval among Republicans is now a record 94 percent — up six percentage points since January. The more Democrats tried to take him down, the more Republicans have united behind the president.

Third, the failure of their impeachment drive has dispirited the Democratic base. An Associated Press poll finds that just 33 percent of Democrats are excited about the 2020 election. At the Iowa caucuses, where Democratic voters had their first chance to show their enthusiasm for replacing Trump, turnout was a dismal 170,000 — a 30 percent decline from 2008, when 240,000 Iowans turned out to give Barack Obama his first presidential primary victory.

Fourth, impeachment has put moderate House Democrats in grave peril. A New York Times/Sienna College poll recently found that almost two-thirds of voters in six battleground states who cast their ballots for Trump in 2016, but then voted for House Democrats in 2018, plan to back Trump again in 2020. That’s bad news for the 31 House Democrats elected in Trump districts in the midterms. How many people are going to vote to give Trump a second term and vote for the Democrats who tried to take away their right to do so? Not many.