The poll numbers favor the challenger; the money's on the incumbent's side.

Bob Casey

Rick Santorum

Fifteen months before their widely anticipated face-off, Pennsylvania Treasurer Bob Casey continues to lead U.S. Sen. Rick Santorum in early polling, while the Republican incumbent has a big advantage in the resources needed to try to change those survey numbers.

The latest Quinnipiac University poll, released yesterday, showed Casey, the likely Democratic nominee in the 2006 race, with a 51 percent to 39 percent advantage over Santorum, a margin consistent with other polls of the race, and one that has shown little change since the prospect of a Casey challenge emerged earlier this year.

Spokesmen for both candidates urged caution in interpreting the results of such trial heats this early in the race. Other questions in the poll, however, reinforced the notion that Santorum is vulnerable in what is expected to be one of the most hard-fought and closely watched congressional races in the country next year.

As the Quinnipiac survey was being released, both campaigns were poised to file contribution reports, due tomorrow, which will show Santorum with an early advantage of more than 3 to 1 over his expected opponent.

Santorum advisers said the senator's report would show that as of June 30, he had more than $5.6 million on hand in his campaign treasury. The Casey camp expected to report receipts of more than $1.6 million.

A Casey adviser said the campaign was happy with its financial progress, characterizing the total as a relatively robust figure for this early stage despite the fact that they had a later fund-raising start than Santorum. Both sides have a long way to go in a race in which spending, on both sides, could easily top $20 million.

Aside from the trial heat findings in the Quinnipiac poll, which was conducted from July 6 to 10, there were mixed numbers for Santorum.

A slim majority of 51 percent of the respondents said they approved of Santorum's performance as senator, while 35 percent disapproved and 10 percent had no opinion. That was markedly lower than the 60 percent approval rating recorded for Santorum's colleague, U.S. Sen. Arlen Specter, but well above President Bush's 44 percent approval.

Just 45 percent of the respondents said they felt that Santorum deserved re-election, while 38 percent said he did not, and 17 percent were undecided.

Among the random sample of voters, 37 percent said they had a favorable overall view of the senator, while 27 percent said they held an unfavorable view, 17 percent a mixed view and 19 percent said they hadn't heard enough about him to form an opinion.

Casey had a better favorable/unfavorable ratio, but despite an extensive history in statewide office, was less well-known to voters. For the Democrat, the evaluations were: 39 percent favorable, just 9 percent unfavorable, 17 percent mixed and 36 percent said they didn't know enough about him.

Casey is the heavy favorite to win the Democratic nomination for the right to challenge Santorum. At this point, he faces at least one Democratic rival, Chuck Pennacchio, a Philadelphia college teacher, in next year's primary.