Rick Santorum plans to lead a strong pro-Romney effort at the Republican National Convention in Tampa, Fla., that can serve as a counterweight in case Representative Ron Paul and his supporters “are looking for a platform fight,” he said in an interview that was broadcast on Sunday.

Mr. Santorum, the former Pennsylvania senator, had sharp differences with Mitt Romney when both were seeking the presidential nomination, but since bowing out of the race, Mr. Santorum has thrown his support behind the presumptive nominee and has papered over their differences.

The same cannot be said of Mr. Paul, the Texas libertarian who is still technically a candidate and who will be bringing more than 200 delegates to Tampa. Mr. Santorum, appearing on the ABC News program “This Week,” suggested that fireworks with the Paul group were a distinct possibility.

Asked about his own interest in influencing the Republican platform, Mr. Santorum said, “I like the platform that we have right now.”

He then added: “I’m concerned that Ron Paul and some of his supporters out there are looking for a platform fight. And I want to make sure that we have strong, principled conservatives there who stood with me in our primary fight to go there and counterbalance the effect of the Paul folks.”

Mr. Santorum, who often sparred with Mr. Paul in the Republican debates, did not elaborate on what shape a platform fight might take.

But Mr. Paul believes in sharply reducing the United States’ entanglements overseas, and he does not believe that government has a role in some of the conservative social causes that Mr. Santorum strongly supports. But despite policy differences between Mr. Romney and Mr. Paul, the two are known to have a good personal relationship.

Mr. Santorum said on Friday in Illinois that he would work in the coming months — in part through a new conservative PAC called Patriot Voices — to ensure that his allies arrive in Tampa “armed and ready to engage the fight.”

On “This Week,” he said that he had not been contacted by Mr. Romney about a possible spot on the Republican ticket. But he made his support clear, saying, “I’ll do whatever I can to be helpful to him.”

Which may, it seems, include doing battle with Mr. Paul.