Behind the scenes, he was scrambling to find money to save the jobs of several aides after losing the payroll authority that came with his position as senior Republican on the Judiciary Committee and various subcommittees.

Mr. Specter also issued a statement on Wednesday insisting that he would ultimately regain his seniority on Senate committees, which Democrats for now have stripped away. But there are no guarantees.

So it goes for Mr. Specter, a political chameleon who started out as a Democrat, spent 43 years as a Republican and abruptly switched parties last week in a naked bid to save his political career.

Mr. Specter, who is up for re-election next year, concluded that he could not win a Republican primary.

But he is having trouble fitting in. He voted against the Democrats in his first two big votes since the switch, opposing the Democratic budget and helping defeat a measure to allow bankruptcy judges to modify mortgages for troubled homeowners.