As the Islamist militia group ISIS gains new ground in Iraq, capturing four more towns near the Syrian border and barreling towards Baghdad, Sen. Rand Paul (R-Ky.) is holding strong to his belief that the United States should stay out of the conflict in the region.

On CNN's "State of the Union" Sunday, Paul ruled out ground troops in Iraq and said that as president, he would ask Congress before getting involved at all.

"There needs to be a full-throated debate in Congress, and Congress has to decide," Paul said. "Militarily, we could go back in. The surge worked. Obviously, we have the military might and power. But the country as a whole has to decide, do we want to send 100,000 troops in? Are we willing to have 4,500 young Americans die to save a city like Mosul that the Shiites won't even save, that they have fled?"

President Barack Obama is sending 300 troops into Iraq as advisers, but he is holding back more substantial military support, including airstrikes and combat troops, for the time being.

Paul also responded Sunday to some of Obama's critics in the Republican Party, who say he should have overthrown Syrian President Bashar Assad following evidence that he used chemical weapons on citizens last year. Paul said we need less involvement in the region, not more.

"We went into Libya and we got rid of that terrible Qaddafi, now it's a jihadist wonderland over there," Paul said, referring to Libya's former dictator. "There's jihadists everywhere. If we were to get rid of Assad it would be a jihadist wonderland in Syria. It's now a jihadist wonderland in Iraq, precisely because we got over-involved."

Paul said he does not believe ISIS currently poses a national security threat to the U.S. It's going to be a civil war, he said, in which the U.S. military has no business being involved.

"You have to ask yourself, are you willing to send your son, am I willing to send my son to retake back a city, Mosul, that they weren't willing to defend themselves?" Paul said. "I'm not willing to send my son into that mess."

Former Vice President Dick Cheney strongly disagreed with Paul on Sunday.