[Read more about the decisions facing House Democrats on impeachment.]

Democratic leaders are sharply divided on whether to pursue an impeachment effort against Mr. Trump, with House Speaker Nancy Pelosi and several presidential candidates uneasy about a Democratic-led impeachment attempt and preferring to let voters judge Mr. Trump in the 2020 election.

Democrats are mindful that the Republican-led impeachment of President Bill Clinton in the late 1990s was a political boomerang on the G.O.P. that contributed to the party suffering deep losses.

But some progressives are appalled at the prospect that Democrats would turn a blind eye to what they believe is criminality in the Oval Office, even if it may complicate their electoral prospects next year.

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Ms. Warren’s call for impeachment comes as she is laboring to stand out in a sprawling Democratic field and is looking for opportunities to create contrasts with her rivals in the primary.

Her comments stood in contrast to much of the rest of the Democratic field, as several other candidates for president have treaded carefully around the impeachment question since the Mueller report was released.