Rasmusssen is out with results in the Demoratic primary for the Pennsylvania Senate race showing incumbent party-switcher Arlen Specter leading challenger Joe Sestak by a narrow four point margin, 46 to 42, with ten percent undecided.

The new numbers represent an eight point jump in support for Sestak and a one point decline for Specter since last month's survey.

It should also be noted that Rasmussen's poll of likely Democratic primary voters shows Sestak winning a much larger percentage of support (and thus has the race significantly closer) than any of the other most recent polls, all of which surveyed registered voters.

--------------------------------------------
Follow the RCP Blog on Twitter.
Become a fan of RCP on Facebook.
--------------------------------------------