Sen. Rick Santorum (R) might be damaging his relationship with senior Sen. Arlen Specter (R) with his tough immigration talk, the Philadelphia Inquirer reports today. They say he’s using his colleague as a “political piñata,” but Santorum’s the one who will get hurt if he loses Specter’s support.

Specter helped write an immigration bill that Santorum claims is too soft and offers “amnesty” for illegal immigrants. "Sen. Santorum is entitled to his views," Specter said at a field hearing on the issue. "'Amnesty' is a buzz word that is used in derogation. I think we're moving past that."

The article profiles the “curious and mutually beneficial relationship” between the moderate and the conservative. Specter says he owes his 2004 win to Santorum, who defended him from a conservative challenger, and that he will try to return the favor this year. So far, he has helped Santorum fundraise and co-sponsored his stem-cell research bill last month.

Analysts think Santorum has gone after illegal immigration to shore up his conservative base and distance himself from his colleague. His first TV ad explains that while his Italian family came to America to work, “today some enter our country with more sinister intentions.” A couple weeks ago he visited a cheesesteak restaurant whose owner put up a sign saying, “This is America. When ordering, please Speak English.”

Other observers are confused, because illegal immigration isn’t a very contentious issue in Pennsylvania. "To be honest with you, we could use some immigration," Joseph Sabino Mistick, a political analyst and columnist for the Pittsburgh Tribune-Review said. The state is 86 percent White and only 3.8% Hispanic.

Even so, Rep. Jim Gerlach (R-06) is adopting Santorum’s tactics: his first ad is also about illegal immigration. Gerlach is facing a challenge from Lois Murphy (D). In his district, at least, the issue is a little more relevant—the city of Reading is home to a significant number of immigrants.