Nancy Pelosi Elected Speaker as Democrats Take Control of House

WASHINGTON — Ebullient Democrats assumed control of the House on Thursday and elected Representative Nancy Pelosi of California speaker, returning her to a historic distinction as the first woman to hold the post. They then moved to force open government agencies shuttered by an impasse over President Trump’s border wall.

On the first day of divided government in a reordered Washington, Ms. Pelosi, now second in line to the presidency, and Mr. Trump clashed from their respective ends of Pennsylvania Avenue almost from dawn until dusk. The California Democrat began her day by suggesting that a sitting president could be indicted. Late in the day, Mr. Trump made an attention-getting appearance in the White House briefing room with a belligerent demand for a wall on the Mexican border.

In between, as the start of the new House majority showcased a younger and more diverse majority in the staid corridors of the Capitol, Ms. Pelosi pledged to run a “unifying” Congress that would bridge partisan divides and heal rifts in a polarized country.

“Our nation is at a historic moment,” she declared. “I pledge that this Congress will be transparent, bipartisan and unifying, that we will seek to reach across the aisle in this country, and across divisions across our nation.”