From the Ezra Klein post that Charles linked too:
“And still, it looks like Democrats might lose the vote today. And when I say “lose the vote,” I don’t mean that a majority of the Senate will vote against it. I mean that 58 senators, rather than 60, will support the legislation. All Republicans, and possibly Ben Nelson, appear to remain opposed. And why not? The less that Democrats appear to be doing on jobs — and the fewer jobs that Democrats actually create — the better Republicans will do in November. Substantial compromises on the bill haven’t brought any new votes, and that’s in part because Republicans see no political upside in passing the legislation.”

So in the end the R’s really don’t give a shit.
If the bill does not pass they can blame it on the D’s even though they got compromise after compromise and still said “no”. We suck as a country if there is no political downside to voting against help for the unemployed in this economy.