Via Taegan Goddard, Sen. Arlen Specter (D-PA) is currently sitting on a 13 point lead over Rep. Joe Sestak (D-PA) in the 2010 Pennsylvania Senate primary. A big lead, to be sure, but one that's dipping rather quickly. In June, Specter's lead was significantly greater. At the time, according to Rasmussen, Specter led Sestak 51-32--a 19 point margin.

Now, the spread is 47-34, meaning, among other things, that his support among Pennsylvania Democrats has dipped under 50 percent for the first time since he switched parties.

According to Rasmussen, "Among voters who favor the congressional health care plan, Specter leads 55% to 26%. However, among those who oppose the plan, Sestak leads 61% to 25%." It's unclear how this divide emerged, but since support for reform among Democrats in the state is around 70 percent, don't be surprised if you see both candidates try to stake out the reformer position on health care.