You know an incumbent is in tough shape when it's considered good news that his challenger is just nine points ahead, but that's where Pennsylvania Senator Rick Santorum (R) finds himself seven months before Election 2006.

The latest Rasmussen Reports election poll in the Keystone State shows Democrat Bob Casey leading Santorum 50% to 41%. That's the first time in all six polls we've conducted on this race that Casey's lead has slipped to single digits. It's also the first time Santorum has moved above the 40% mark since last July.

However, another aspect of the poll might be even more encouraging for Santorum... and troubling for Casey.

After asking survey respondents who they would vote for, we informed them that the National Organization for Women (NOW) is concerned about Casey on the abortion issue and is endorsing another candidate in the primary. We then asked a second time about how each respondent would vote.

Twenty-four percent (24%) of Casey's initial voters changed their mind upon hearing this news. Half switched to Santorum while the others split between "some other candidate" and "not sure."

The change was dramatic enough that, having heard the new information, voters favored Santorum by a five-point margin (46% to 41%). This suggests a lack of voter knowledge about Casey that could make the race more competitive than it seems at this time.

News about NOW's concerns caused Casey's support to fall 12 points among moderate voters and 13 points among liberal voters. It did not gain him any conservative votes.

From a partisan perspective, Casey lost 7 points of support among unaffiliated voters and 13 points among Democrats. Just as important, however, the highlighting of Casey's pro-Life views actually increased Santorum's support among Republicans.

Initially, the GOP voters favored Santorum by a 61% to 27% margin. On the second ask, they favored Santorum 69% to 21%.

Despite all of this, however, it is important to remember the basic fact that Senator Santorum remains in terrible shape for an incumbent. It may be possible for him to mount a comeback, but it will be uphill all the way.

The rolling average of the last three Rasmussen Reports Pennsylvania election polls shows Casey continuing to hold a solid lead, 50% to 38%. In other words, while Casey's support may be declining slightly, it has not yet transformed the nature of this race.

Crosstabs are available for Premium Members.