Ask ole Joe if would vote for Harry Reid for Majority Leader
There’s a video of Manchin supporting Obama and Obamacare:
http://www.c-spanarchives.org/program/ID/220989&start=4192&end=4268
In the Senate, they don’t actually vote for Majority Leader; the leader of the party with the most members in its caucus automatically becomes majority leader. Thus, the question to Manchin would be “if you are elected, would you caucus with the Democrats even though it would make a liberal Democrat such as Chuck Schumer or Dick Durbin Majority Leader?”