I Can't Count

All I've heard from the administration and the media regarding Obama's job bill is, "the Republicans shut down the bill". I always thought there were 100 senators and, at present, 52 were slugs, er, democrats. Okay, 52 vs. 48 means a majority. So, who were the people who voted against the jobs bill? Do ya' think they might have been dems who are in danger of losing their senate seats in the next election?