The bad news keeps coming for Pennsylvania's senior Republican Senator Arlen Specter. Yesterday it emerged that far right activist and former Congressman Pat Toomey, who nearly knocked off Specter five years ago, is considering another primary challenge this cycle. Now new polling released today indicates that Specter might not only not have a great shot at being renominated in the event of a challenge by Toomey -- he might not have any shot at all.

A new statewide poll shows 53 percent of Pennsylvanians -- and 66 percent of Republicans -- want someone to replace Sen. Arlen Specter.

Asked whether they think Specter, a Philadelphia Republican, has done his job well enough to win re-election or whether they'd prefer a "new person" in that job, registered voters by a 53-38 percent margin said it's time to give someone else a chance, according to the poll by Susquehanna Polling and Research. Eight percent were undecided.

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Among registered Republicans, 66 percent favored a new senator and 26 percent backed Specter. The margin of error on that question was plus or minus 5.9 percentage points.

Even considering the rather large margin of error for the subsample of Republicans, this has got to have Specter worried -- and thinking. Remember, the universe of Republican primary voters tends to be significantly more conservative than the universe of all Republicans.

So what can Specter do at this point? It seems unlikely to me that he would opt against running for a sixth term in the Senate -- that just doesn't seem like the Arlen Specter we have all come to know over the years. But he has to realize that he wouldn't have much of a shot in a Republican primary against Toomey, even as he would would have a shot at reelection running as an independent (nearly twice as many Democrats as Republicans want to see him reelected).

I don't know enough about Pennsylvania election law to determine whether Specter could pull a Joe Lieberman -- running in his party's primary, but holding out the possibility of running on his own ticket in the event he lost the primary -- but I'd imagine that Specter's team already knows the answer. It may be that Specter would even forgo the attempt to run in a Republican primary against Toomey or a similarly strong conservative. Then again, Specter isn't one who has tended to give up on fights in his career, so maybe he would opt to enter what appears to be a nearly unwinnable primary just to prove his political courage. Either way, this is shaping up to be one of the most interesting races of the cycle.