Senator Joe Manchin (D-WV) has announced he will not stand for reelection. His state is mostly Republican and reelection was going to be a challenge anyhow.
Manchin is his party's version of Mitt Romney, a guy going his own centrist way while his party becomes more extreme. He claims he will travel the country "exploring" whether there is support for a middle-of-the-road independent candidacy. Maybe Joe and Mitt should team up?
Someone suggested perhaps he'd like the presidency of the U. of West Virginia, as a valedictory career move. That sounds more realistic.