“It lit up our base,” Mr. Parscale said. “They see their vote is trying to be stolen from the 2016 election.”

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He added that impeachment meant that it took “less advertising” to fill up the stadiums where Mr. Trump holds rallies, and that it “puts money in our bank and adds volunteers to our field program.”

Mr. Parscale and others at the briefing outlined a robust campaign operation that plans to compete in states that Hillary Clinton won in 2016, like Minnesota and New Hampshire.

They said they had $93 million in cash on hand, two million volunteers across the country and more than 330 field offices in 17 critical states. Campaign officials said they planned to introduce Jewish Voices for Trump, Evangelicals for Trump, Catholics for Trump and Cops for Trump as stand-alone groups next year.

They said that 8.8 million voters who were “very enthusiastic” about Mr. Trump in 2016 did not show up for the 2018 midterm elections because the president was not on the ballot. But they said those voters remained enthusiastic about Mr. Trump and were expected to turn out in 2020.

Most notably, Mr. Trump’s advisers laid out how many more votes he got in key Midwestern states than Mitt Romney did as the Republican presidential nominee in 2012. And they pointed out that presidents historically see fluctuations in their approval ratings in the period before their re-election efforts.

In response, Democrats said it was impossible to measure whether impeachment was really creating activity among Trump supporters that the campaign would otherwise be unable to harness — and that what the Trump campaign officials failed to take into account was the grass-roots energy it created on the other side of the aisle.