Thomas Rhiel August 6, 2010, 5:33 PM

Rasmussen’s out with some new numbers from the seldom-polled Delaware Senate race for Joe Biden’s old seat, and it looks like Democrat Chris Coons’s chances will depend upon which GOP nominee gets the nod.

Republican Rep. Mike Castle has a 49%-37% lead over Coons, a margin a tad wider than the 47%-36% lead he had in Rasmussen’s July 14 poll. Coons, in turn, has a 46%-36% lead over Republican Christine O’Donnell, theTea Party Express-endorsed Republican in the race. Support for O’Donnell has flagged since July 14, when she led Coons 41%-39%, and her unfavorable rating has jumped from 33% to 38%. Castle is the favorite in the September 14 Republican primary.

The TPM Poll Average of the race gives Castle a 52.0%-32.8% lead over Coons. There hasn’t been enough polling of a Coons-O’Donnell matchup to develop a TPM Poll Average. The margin of error of the latest Rasmussen poll is ±4.5 percentage points.

Check out TPMDC’s full coverage of the race here.

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