Sen. Tim Johnson (D-SD) has been hospitalized. If he is unable to complete his term in the Senate (which goes through 2008), Gov. Mike Rounds (R) would appoint a replacement. Remember, Rounds is the one who signed the state abortion ban (recently repealed by a popular referendum), so he clearly wants a Senate who will approve Bush's wacko judicial nominees. If the replacement senator is a Republican, this will shift the balance of the Senate to 50-50 (assuming both independents continue to caucus with the Democrats), with Dick Cheney breaking the tie.
So all we can do is pray for Sen. Johnson's full and speedy recovery. Please add Tim ben Noach to your mi shebeirach.