Joe Manchin is at the center of an extremely divided Washington. Here's how he got here.

Democratic Sen. Joe Manchin of West Virginia is a key vote crucial to President Joe Biden's agenda with Capitol Hill bitterly divided along partisan lines.

Manchin has long been in the spotlight in Washington as a pivotal swing vote unafraid to break with his party over high-profile issues. But the focus on the conservative West Virginia Democrat has intensified in the early days of the Biden administration with Democrats controlling the narrowest possible majority in the Senate, which means the votes of every lawmaker carry outsized weight. Facing GOP opposition to key Democratic priorities, many Democrats have intensified calls for the elimination of the filibuster, which sets a 60-vote threshold for most legislation and can be wielded by Republicans to block liberal agenda items. But Manchin has been a thorn in the side for those who want to get rid of the procedural tool as he has continued to make clear he won't vote for its elimination.