CLINTON, Iowa—Before President Trump, no American president had ever sought re-election in the middle of an impeachment. Former Vice President Joe Biden is contending with a similar distinction in the Democratic primaries, as a White House candidate caught up in the impeachment of Mr. Trump, whose trial centers around his pressing Ukraine to investigate Mr. Biden, a possible opponent in this year’s election.

Source: Wall Street Journal January 29, 2020 19:18 UTC