"I think the court is likely to invalidate the individual mandate. This is something that for most Americans offends their basic sense of freedom, and this is not something they want. I think the justices also understand this does not stand within the Congress's enumerated powers," Lee told CNN on Thursday.

The Utah lawmaker said speculation that Chief Justice John Roberts, appointed by former President George W. Bush, would be delivering the majority opinion boded well for opponents of the law. Lee said the fact that Roberts seemed personally skeptical of the law's individual mandate during oral arguments earlier this year would indicate the law was in trouble.

"I took this as a pretty strong indication as to which way he leans in this case, so, if he assigned himself the opinion, that means he's in the majority, which means the majority of the justices are likely against the individual mandate," Lee said.

But Lee acknowledged that although conservatives will win a victory if the Affordable Care Act is gutted, they could be handing Democrats a potent political weapon if children, college students, and those with pre-existing conditions lose care they had been assured of under the president's plan.

"I think those will certainly be issues not just for Democrats but for Republicans. We're going to have to address this step by step," Lee said.

The senator also defended the high court from widespread criticism that recent decisions have become increasingly politicized. A recent Bloomberg poll showed some three-quarters of Americans believed the justices acted on personal or political bias.

"These justices do approach the law from their own different philosophical vantage points, but that's not the same as saying they're politically charged," Lee said.