NBC news noted that he "seemed to compare President [Barack] Obama to [Adolf] Hitler."

The former Pennsylvania senator told his supporters that this election was like World War II, "where our closest ally, Britain, was being bombed and leveled."

"And America sat from 1940 when France fell to December of '41 and did almost nothing," he explained. "Why? Because we're a hopeful people. We think, 'You know it will get better. Yeah, I mean, he's a nice guy. It won't be near as bad as what we think. You know, this will be OK. You know, maybe he's not the best guy.' After a while, you found out some things about this guy over in Europe and maybe he's not so good of a guy after all. But you know what? 'Why do we need to be involved? We'll just take care of our own problems, just get our families off to work and our kids off to school and we'll be OK.'"

The candidate added: "Sometimes, sometimes it's not OK."

As BuzzFeed pointed out earlier this year, it's not the first time Santorum has compared his opponents to Adolf Hitler.

During a 2005 speech on the Senate floor, the then-senator blasted Senate Democrats for complaining that Republicans were trying to stop them from filibustering President George W. Bush's judicial appointees.

"It's the equivalent of Adolf Hitler in 1942: 'I'm in Paris. How dare you invade me? How dare you bomb my city? It's mine,'" he said.

Over the weekend, Santorum also said that Obama's theology was not "based on the Bible." He later clarified that he wasn't questioning if the president was a Christian.