The charges intensified the administration’s efforts to go after the law enforcement and intelligence personnel who cast doubt on unsubstantiated claims that Joseph R. Biden Jr. engaged in corrupt dealings in Ukraine.

© Erin Schaff/The New York Times

Jeffries, who is in line to become House speaker if Democrats seize the majority, has traveled to some 50 cities campaigning for Democratic candidates.

Ever the optimist, Speaker Mike Johnson said he believes Republicans will hold on to their U.S. House majority, defying a surge of Democratic momentum in the final stretch of the midterm elections that will determine control of Congress.