Coons leads conservative activist Christine O’Donnell, who is challenging Castle for the GOP Senate nomination in a primary next Tuesday, by a 47% to 36% margin. Given that matchup, eight percent (8%) prefer another candidate, while nine percent (9%) are undecided.

Last month, Coons held a similar 46% to 36% lead over O’Donnell after the candidates were virtually tied in July.

Castle captures 71% of the GOP vote, while O’Donnell earns 63% support among voters in her own party. While Coons is backed by 70% of Democrats against O’Donnell, he earns the vote from just 55% of Democratic voters when matched against Castle. Voters not affiliated with either major party prefer Castle over Coons but favor the Democrat if O’Donnell is his opponent.