Now that the U.S. Supreme Court has upheld President Barack Obama's health care reform law, will Fox News host Bill O'Reilly apologize? After all, he promised he would.

During a March 26 interview with American Constitution Society President Caroline Fredrickson, O'Reilly ended the interview by promising to "apologize for being an idiot" if the court upheld the law.

The American Constitution Society President had argued that the law was constitutional based on Commerce Clause and Congress' power to collect and spend revenue for the general welfare.

After O'Reilly threatened to end the interview if Fredrickson would not name one thing the federal government forces people to buy, she explained that the Affordable Care Act imposes a penalty, but does not "force" people to buy health insurance.

"It's a form of a tax," she told the Fox News host.

"It's a police power," O'Reilly interrupted. "This is becoming absurd. It's a police power if you punish someone for not doing anything!"

"Sir, you're going to have to let me talk if you invite me on your show," Fredrickson pointed out.

"No, I don't have to let you talk if you're not answering the question," O'Reilly shot back.

"Ms. Fredrickson, you're going to lose and your arguments are specious," he added. "It's absolutely police powers from the federal government and it's going to be 5 to 4. And if I'm wrong, I will come on and I will play your clip and I will apologize for being an idiot."

"I look forward to it," Fredrickson said.

In a 5-4 decision on Thursday, the Supreme Court on Thursday upheld the Affordable Care Act on the basis that the law's individual mandate was a tax.

Watch this video from Fox News' The O'Reilly Factor, broadcast March 26, 2012.