Sen. Scott Brown joked at a St. Patrick's Day that Republican presidential hopeful Rick Santorum's secret service detail may be the first time he's ever "used protection."

"I'm hopeful that all of you are actually following presidential politics. I see that both Newt Gingrich and Rick Santorum now have secret service with them on the campaign trail and in Santorum's case, I think it's the first time he's actually ever used protection, so yeah, yeah. Just saying," Brown said.

Buzzfeed posted a video today of the Republican Massachusetts senator at the event.

The joke was a jab at Santorum's stance against contraception. The former Pennsylvania senator has repeatedly said he believes the use of birth control is morally wrong and that he supports proposed legislation that would allow companies to deny health insurance coverage of birth control to its employees if it conflicts with the company's views.

Eric Ferhnstrom, a senior adviser to Mitt Romney's campaign, is also an adviser to Brown.

Brown also took the chance to poke fun at Newt Gingrich over his moon colony proposal and at Ron Paul.

"And I know that, you all know that Newt Gingrich wants to build a colony on the moon," he said. "Forget the moon. I think he should build it on whatever planet Ron Paul's from. That'll work."