Manchin will not flip if the Republicans take the Senate he would be the odd one out in the caucus. He voted for raising the minimum wage, equal pay, funding Obamacare and on most Democratic bills brought up on the Senate floor.
Exactly. People get so hung up on social issues and cultural issues. Manchin is as much of a Democrat as any other.
No, he's one of the most conservative Democrats in every category.
http://www.progressivepunch.org/members.htm?member=412346
Sure, but he isn't more conservative than any Republicans on the whole (though he may be to the right of Murkowski, Kirk, Portman, and Collins on LGBT issues alone).
That's because the Republican party is just right-wingers now.