"If Manchin, Nelson and Lieberman switched, it would leave the Senate in a 50-50 deadlock."

"Republicans believe Manchin is particularly susceptible to the overture because he is up for reelection in 2012 and will have to be on the ticket with President Obama, who is direly unpopular in West Virginia. Democrat Ben Nelson of Nebraska and Independent Joe Lieberman are the other two prime targets of Republican advances."