WASHINGTON - As President Donald Trump prepares for only the third impeachment trial in American history, no one may be more important to his defense than the Kentucky Republican in charge of the Senate, Majority Leader Mitch McConnell.

The Democratic-run House is set to transmit the articles of impeachment to the Senate in a matter of days.

McConnell faces the challenge of balancing Trump's appetite for full vindication, accompanied by humiliation of Democrats, with a more measured trial that fits the legal expectations of the Constitution.

McConnell is also trying not to expose Senate Republicans to a spectacle that could hurt them in elections.