Sen. Arlen Specter has a 12-point lead over Rep. Joe Sestak in the Democratic primary, according to new poll results.

Specter led Sestak 30 percent to 18 percent, with 47 percent of respondents undecided in the Democratic primary.

In a similar poll from the end of August, Specter led Sestak by a larger margin, 37 percent to 11 percent, among registered Democrats.

Specter announced in April that he was switching parties to run for re-election as a Democrat because he said polls showed he could not win the GOP nomination over former Rep. Pat Toomey.

In this most recent survey, Specter only had a small lead within the margin of error over Toomey in the general election. Specter led Toomey 33 percent to 31 percent, with 30 percent undecided in the poll.

The survey, taken Oct. 20-25, polled 529 registered voters and had a margin of error of 4.3 points. The subsample of 250 Democratic registered voters had a margin of error of 6.2 points.

Franklin and Marshall College administered the poll, which was paid for by several local news organizations.