Yet another poll showing that Arlen Specter is losing his mojo for the 2010 Senate race. This comes courtesy of Rasmussen:

The latest Rasmussen Reports telephone survey of Pennsylvania voters shows 45% would vote for Toomey if the election were held today. Forty percent (40%) would vote for Specter, while six percent (6%) prefer a third option. Nine percent (9%) are undecided.

If Sestak wins the Democratic nomination, however, the race is a toss-up: 38% for [Democratic Congressman Joe] Sestak and 37% for Toomey.

That’s actually an improvement for Specter, who Rasmussen showed trailing Toomey by double-digits this summer, at the height of the healthcare fracas. And for what this is worth, Rasmussen has a reputation for skewing conservative.

But what’s most interesting to me is that this poll shows that Joe Sestak appears to be viable, and electable … despite the fact that Gov. Ed Rendell and other powerbrokers have lined up behind Specter.

Sestak was in our office recently, and I’m going to do a blog post about that encounter by day’s end. For now, suffice it to say that it’s pretty clear what’s driving the numbers here: Republicans are more excited about beating Specter than Democrats are about electing him. From Rasmussen:

Eighty percent (80%) of Republican voters now favor Toomey in a match-up with Specter while the incumbent senator draws just 65% of the Democratic vote.