In the final sprint to the election, Kamala Harris’ campaign — at her insistence, aides and allies said — started playing Donald Trump’s most incendiary comments on the jumbotrons at her rallies, displaying in technicolor his meandering, racist and, sometimes, violent rhetoric.

In the wake of Donald J. Trump’s resounding victory, many Democrats are casting President Biden as a one-term president who set his party on a path to failure in 2024.

Democrats are directing their rage over losing the presidential race at Joe Biden, who they blame for setting up Kamala Harris for failure by not dropping out sooner. They say his advancing age, questions over his mental acuity and deep unpopularity put Democrats at a sharp disadvantage.