Sen. John Kerry (D-MA) said the law has been thoroughly vetted.
"As a senior member of the Finance Committee," he said, "I can tell you that we had one of the most rigorous and transparent legislative processes that I have witnessed in almost 3 decades here in the Congress. We worked with some of the brightest, most thoughtful and experienced constitutional lawyers in order to make sure that the law was constitutional."
Kerry said the assumptions that tough questions from the justices will amount to striking down some or all of the Affordable Care Act are a fallacy -- he predicted, as the final oral arguments were transpiring inside, that it would be upheld.
"Now I am glad -- as I think any of us who've practiced law are -- to see the intense questions from the justices. They're engaged, and they are thoughtfully working through these issues," Kerry said. "But questions are a legitimate way of probing the basis of their own thinking. They are not an indication of a judgment made, or a vote ready to be cast. They're working through this process as they ought to, mindful of the fact that 30 courts below them have already made a judgment upholding it."
Blumenthal and Kerry -- who were joined by Sen. Jeff Merkley (D-OR) -- called the press conference one day after liberals and other court watchers expressed serious doubts that the justices would uphold the Affordable Care Act's requirement to purchase insurance, a central pillar of the law. The firestorm was ignited by legal analyst Jeffrey Toobin, who called Tuesday's arguments a "train wreck" for the White House and predicted that "Obamacare" would be struck down.
Pushing back, Blumenthal said that there's a "heavy burden" on the challengers.
"Everybody learns in the first year of law school that the law that's challenged is presumed to be constitutional," Blumenthal said. "That is a heavy burden for anyone challenging the constitutionality of a law to overcome. When in doubt, uphold the law. There is a lot of room for doubt here, and there is a lot of clear precedent that requires this court to uphold this law."
The Democrats' level of confidence has diminished since the days when they dismissed a constitutional challenge to the Affordable Care Act as frivolous. Indeed, the tough questioning from swing Justices John Roberts and Anthony Kennedy about the limits of federal power at least rattled liberals enough to require the nerve-soothing press conference. But Democrats are seeking to quell liberal fears that the game is already over.
Experts say it's too difficult to predict how the court will rule.