McCain had asked Buttigieg to clarify a previous statement he made about the Bible claiming that life began with a breath.
"I'm just pointing to the fact that different people will interpret their own moral lights and for that matter interpret scripture differently," he told McCain.
He added that in the United States, no one should be subjected to another person's religion. When McCain pressed him for a specific limit on abortions, Buttigieg suggested that wasn't his responsibility.
"My point is that it shouldn't be up to a government official to draw the line. It should be up to the woman who's confronted with the choice,' Buttigieg said.
Buttigieg's comments came amid a nationwide battle over legal access to abortion. Officials like Virginia Gov. Ralph Northam came under fire for statements supporting looser restrictions. Northam, in particular, backed the decision to withhold care from infants based on the decision of mothers.
"When we talk about third-trimester abortions, these are done with the consent of obviously the mother, with the consent of the physician — more than one physician, by the way — and it’s done in cases where there may be severe deformities. There may be a fetus that’s non-viable," Northam said.
"What if a woman wanted to invoke infanticide after a baby was born -- you'd be comfortable with that?" McCain told Buttigieg. Buttigieg balked at McCain's argument, asserting that late-term abortions involved women who intended to carry their babies to term and get "the most devastating news" of their lives.
"We're talking about families that may have picked out a name -- may be assembling a crib -- and they learn something excruciating and are faced with this terrible choice -- and I don't know what to tell them morally about what they should do. I just know that I trust her and her decision medically or morally isn't going to be any better because the government is commanding her to do it in a certain way," he said.
McCain told him that was a radical position.
"I respect what you're saying because you didn't back down from it. This is going to hurt you in the middle of the country with the Republicans you're trying to win over. People like me, this is a hard line and quite frankly, that answer is just pretty ... just as radical as I thought it was," she said.
Buttigieg previously faced scrutiny over the issue when Kristen Day, executive director of Democrats for Life, asked him whether there was room in the party for pro-lifers like her. Buttigieg similarly told Day that he thought women should be able to make the decision.