If Specter cares about being re-elected he will oppose this thing. If he votes for it, he will get no goodwill or support from Democrats - they will seek to aggressively defeat no matter how he votes. Plus, voting in favor of this thing virtually guarantees a conservative primary challenge, and this time he won’t have Bush and Santorum to bail him out. I can’t imagine him surviving a primary challenge if he supports the stimulus.
Spector has now seen that no Pubs voted aye in the House. Maybe his little pee brain will calculate what will happen if he votes aye in the Senate!