In it, but not of it. TPM DC
From the pollster's analysis:
It's clear that Castle's popularity has taken a sharp turn in the wrong direction over the last month. An August PPP poll found his favorability with Delaware Republicans at a 60/25 spread. Now his favorables within the party are negative at 43/47. That's largely a product of 55% of voters in his party saying they think he's too liberal compared to 37% who think he's about right.
GOP voters are pretty sharply divided about O'Donnell as well. 45% have a favorable opinion of her with 41% seeing her unfavorably. Only 50% of primary voters think she's fit to hold public office but she does much better than Castle on the ideology front- 53% think she's about right.