51 Dems/49 Pubs. If Johnson can't vote, 50 Dems/49 Pubs. Should he be replaced with a Republican, the number would be 50/50 from each party. Given the number of RINOs, the left still holds a majority even if the party affiliation is evenly split.
good points
You're figuring the two Independents (Lieberman and Jeffords) are Donks?
If Johnson can't vote, it's actually 49 Republicans, 48 Dems, 2 Independants. We would hold a one seat majority over the Dems.
Unfortunately, the two "independants" would vote for a RAT leader, and thus the party in the minority would control the Senate. I hope all the Joe Lieberman worshippers on FR are happy they donated time and money to keep his butt in office instead of Talent/Allen/Burns, etc.
Though I do think if Johnson's condition doesn't improve, the Dems would have a MINO (Majority In Name Only). They'd technically run all the committees and have all the leadership positions, but if any Dem is absent at any given time, 49-49 votes would be broken by Dick Cheney.