Explainer: The case for Trump's impeachment - and the case against it

FILE PHOTO: U.S. President Donald Trump boards Air Force One at Joint Base Andrews, Maryland, U.S., December 14, 2019. REUTERS/Tom Brenner/File Photo

WASHINGTON (Reuters) - The Democratic-controlled U.S. House of Representatives will vote on Wednesday to formally charge President Donald Trump, a Republican, with "high crimes and misdemeanours," making him only the third U.S. president in history to be impeached.

That sets up a trial in January in the Republican-run Senate, where he is expected to be acquitted.