Mitt Romney Will Vote to Convict Trump Ahead of Expected Acquittal

WASHINGTON—The Senate is expected to acquit President Trump on charges of abuse of power and obstruction of Congress on Wednesday, bringing to a close the third presidential impeachment trial in U.S. history and one that began with virtually no chance of conviction in the Republican-controlled chamber.

Hours before the expected vote to acquit, Republican Sen. Mitt Romney of Utah, a frequent critic of Mr. Trump’s, said he would vote to convict the president on abuse of power, becoming the only GOP senator to break with his...