Last week's grueling three days of oral arguments at the U.S. Supreme Court left supporters of the health care law somewhat dumbfounded, as they faced the possibility that the justices could strike down President Barack Obama's signature domestic achievement.

But Sen. Chuck Schumer says the tough line of questioning, especially from the justices who will likely cast the deciding votes, is a poor barometer for guessing how they will rule on the health care overhaul this June.

You can't tell by the questioning as to how the court is going to rule, Schumer said Sunday on Meet the Press. Anyone who judges how the court is going to rule based on the questions hasn't looked at the history of the questions before and then the results.

With a possible ruling declaring the Affordable Care Act unconstitutional, Schumer, the Democrats' messaging guru and No. 2 senator, is tamping down expectations based on justices' remarks, the few clues into their thinking that the public receives.

Schumer pointed to conservative judges on the lower appeals courts who asked similarly hostile questions during hearings, yet ultimately found the law and the insurance mandate within Congress' power to regulate interstate commerce.

Further, there is precedent upholding Congress' broad authority under the Commerce Clause to regulate seemingly personal activity, like a growing a small plot of marijuana (Gonzalez v. Raich) or wheat crop for food (Wickard v. Filburn), Schumer noted.

These are the reasons that gave Obama administration lawyers and the legal community in general confidence the justices would ultimately uphold the Affordable Care Act.

But questions from the bench during oral arguments showed a bloc of mostly conservative justices who seemed to side with arguments from challengers of the health care law. That says nothing of the difficulty the Obama administration's chief Supreme Court attorney, Solicitor General Donald Verrilli, had in articulating the government's argument.

Schumer Defends Verrilli's Performance

But Schumer saw criticism of Verrilli's performance overblown, dismissing that he choked because he needed a sip of water during his opening remarks on the insurance mandate.

On the substance, he had very good answers. You know, drinking water, coughing, that's not going to affect these justices, Schumer said. I think the solicitor general on the substance of the arguments did a very good job.

Still, oral argument highlighted the possibility that the justices may strike the law down, a decision that will leave an indelible mark on the Supreme Court as an institution.

Schumer was attuned to that perception of the Supreme Court in light of highly-partisan 5-4 decisions like Bush v. Gore and Citizens United, which upended precedent that supported campaign finance laws.

Should the Supreme Court overturn this law, Schumer said, it would be so far out of the mainstream that the court would be the most activist in a century.

If they were to throw out the health care law, things like Medicare, Social Security, food safety laws could be in jeopardy on the very same grounds, he later added. It would be a dramatic, 180 degree turn of the tradition of the Commerce Clause.