The two candidates debated twice on Monday during which the two quickly moved from issues to the basic claims of each camp: Santorum is simply a rubber stamp for the Bush administration and Casey is a climbing politician more focused on winning a Senate seat than he ever was in doing his job as state treasurer.
"I show up to work," Santorum said in the morning debate at KYW Radio in Philadelphia. "I do my job."
"Don't start this. Everybody works hard, Rick," Casey shot back. "Don't lecture me or anyone else about who works hard."
Santorum repeatedly accused Casey of being unable or unwilling to answer questions about foreign policy or his own record.
"He offers absolutely nothing," Santorum said of Casey. "He dodges and bobs and weaves. All he has tried to do is tear down, tear down."
Casey responded: "He started the attack ads from day 1. If there is anyone who is an expert in negative ads, it is Rick Santorum."
Santorum also questioned Casey's success as a politician, saying it owed more to his father's name than Casey's ability. Bob Casey Sr. was a popular governor of the state.
"The bottom line is I have worked hard for the people of Pennsylvania," Santorum said. "Why? Because I had to work for this job. It is not a job I inherited because of my last name."
For Santorum, the hard ball tactics underscore the dire straights his campaign finds itself with less than three weeks to go. Combined, the two campaigns have raised some $38.8 million, the most in Pennsylvania history, and the latest numbers show both campaigns have about $3.5 million left. That means the financial advantage Santorum carried into the race has evaporated and the two will battle to the end with the same resources.
Santorum has poured more than $20 million into his campaign, while the latest poll shows Casey ahead with 49 percent to Santorum's 40 percent.
"Looking at all of the polls conducted in the state since February, not a single one has shown him ahead of Casey," Berwood Yost, director of the Center for Opinion Research at Franklin and Marshall College, wrote in a Philadelphia Inquirer online chat. "Recent polls, in fact, show Casey with a comfortable lead, although he is not over the magical 50 percent mark yet. Only rarely does a candidate who is consistently behind, particularly in a race that is as heavily polled as this one, win."
Despite the predictions of doom from political pollsters, conservative activists from across the country have poured money and time into the campaign to save the two-term senator.
"I think it's important for people across the country to recognize how important it is not only to pay attention but to get engaged in this race, whatever way they can," Colin Hanna, head of Let Freedom Ring, a conservative group based in Pennsylvania, told The Los Angeles Times. "If Rick Santorum were to lose, it would be cited as a turning point in the social conservative movement."
But neither candidate is betting solely on their traditional supporters to deliver on Election Day. Santorum has taken time to court black voters, pointing to school vouchers and inner city development zones as policies aimed at helping them.
Casey also has campaigned in the strongly conservative central part of the state, saying he is running in the entire state, not just Democratic Philadelphia and Pittsburgh.
"We can't have kind of a blue-state-only strategy in presidential campaigns, and I can't have a blue-county-only strategy," Casey told the Philadelphia Inquirer.
Both campaigns have shifted their focus to ensuring supporters get to the polls on Nov. 7, and even the doomsayers of Santorum say his campaign has proven it can deliver voters. The question remains as to whether Casey carry his lead into the voting booth.