WASHINGTON-President Obama gave an unprecedented ultimatum on a pending U.S. Supreme Court case Monday, saying that if the justices overturned his healthcare law it would be "unprecedented" and amount to "judicial activism." He said he expected the justices to uphold the law.

Other presidents have criticized the effect of Supreme Court decisions before: Ronald Reagan criticized Roe v. Wade and Franklin D. Roosevelt criticized a decision that threw out a bevy of his New Deal legislation. But no president appears to have publicly characterized the court as political activists before, especially not before a decision has been rendered.

Since the arguments last week hinted at the possibility that the high court would overturn the law, Democrats have been preemptively characterizing the justices as partisan judicial activists.

"Should the Supreme Court overturn this law, it would be so far out of the mainstream that the court would be the most activist in a century," said Sen. Chuck Schumer, D-N.Y., who is part of the Senate Democratic leadership, on Meet the Press Sunday.

Former President Bill Clinton said in an interview with MSNBC on Monday that the actual arguments were "unusually politicized." He offered his analysis of the law: "I don't think it was unconstitutional in any way, shape, or form. Even in the 1790s there were mandates. … It's hard to take the constitutional argument seriously. So I think it's more about politics."

Some Republicans shot back. Sen. Orrin Hatch of Utah, former chair of the Senate Judiciary Committee, stated Monday, "It must be nice living in a fantasy world where every law you like is constitutional and every Supreme Court decision you don't is activist."

The Washington Post editorial board, generally considered liberal, also pushed back against liberals' characterization of the court last week (see "Civics lessons from the Supreme Court"): "Sadly, even before the sessions on healthcare reform had ended, some liberals were preemptively trying to delegitimize a potential defeat at the court. … [T]here's a kind of cynicism, or at least intellectual laziness, in asserting that this is an easy or obvious call-that no justice could possibly strike down the mandate out of honest, reasoned conviction. Solicitor General Donald B. Verrilli Jr. had his hands full defending the mandate, not because he's a bad lawyer, but because it's not an easy question." The editorial board said the court should uphold the law, adding, "But it is not, as we said, a slam dunk. We wouldn't assume anyone who disagrees is a hack."

Obama has attacked the court publicly before. In his 2010 State of the Union address, with the justices sitting right in front of him, he eviscerated their Citizens United decision, saying it "reversed a century of law to open the floodgates of special interests-including foreign corporations-to spend without limit in our elections." Justice Samuel Alito shook his head slightly and mouthed, "Not true," at the foreign corporations comment, because the court's decision upheld prohibitions on foreign spending in elections. The congressional Democrats seated around the justices stood and applauded. Alito, along with several other justices, didn't attend the address the following year.

A reporter asked Obama about the case in the White House Rose Garden Monday, as the president was holding a press conference with Mexican President Felipe Calderon and Canadian Prime Minister Stephen Harper. Obama gave a defense of the law, saying, "It's constitutional-that's not just my opinion." He also said the individual mandate paid for other aspects of the law, making it essential-a line that went against the government lawyer's own arguments in the Supreme Court that the mandate was not essential to the law.

Obama's full comment on the Supreme Court was: "Ultimately, I'm confident that the Supreme Court will not take what would be an unprecedented, extraordinary step of overturning a law that was passed by a strong majority of a democratically elected Congress. And I'd just remind conservative commentators that for years what we've heard is, the biggest problem on the bench was judicial activism or a lack of judicial restraint-that an unelected group of people would somehow overturn a duly constituted and passed law. Well, this is a good example. And I'm pretty confident that this court will recognize that and not take that step."

The court will likely issue its opinion in late June.

Read Emily Belz's Web Extra reports on the first, second, and third day of Supreme Court arguments over the healthcare law.

Listen to a report on the Supreme Court hearingson WORLD's radio news magazine The World and Everything in It.