And not just the conservative justices, either — and that spells trouble for Barack Obama and his defense of ObamaCare.  Philip Klein reports from the arguments being made at the Supreme Court today on the health-care reform plan, and the main argument for the constitutionality of its core individual mandate came under attack from the liberal wing of the court:

On the first day of oral arguments in the case challenging President Obama’s national health care law, justices seemed skeptical that the individual mandate should be considered a tax — one of the main consitutional defenses being offered for the law.

To be clear, today’s 90 minutes of oral arguments did not concern the underlying merits of the case, but whether an 1876 law called the Anti-Injunction Act bars the Court from ruling on the suit at this time. Under the Anti-Injunction Act, people cannot challenge a tax in court until after they have paid it, something that would effectively punt the issue until at least 2015. However, there is some overlap between this question and the idea of whether the mandate is a tax, and justices on both sides of the ideological fence expressed skepticism that the mandate should be treated as a tax.

“This cannot be a revenue raising measure, because if it’s successful, there won’t be any revenue raised,” said Justice Ruth Bader Ginsburg of the mandate.

Another liberal on the court, Justice Stephen Breyer, said of Congress’s description of the fine for non-compliance with the mandate, “They called it a penalty and not a tax for a reason.”

Why does this matter?  Congress cannot mandate a penalty for failing to engage in commerce — but it does have the power to tax.  Despite Obama’s protestations during the ObamaCare debate that the mandate was not a tax, his team has been forced to argue that it in fact does qualify as a tax, since that’s the only basis on which Congress can impose such a mandate.  Most people believed that the conservative jurists on the court would object to that definition, but this looks as though skepticism on the constitutionality of the mandate goes wider than first thought.  If Ginsburg and Breyer don’t buy the tax argument, the mandate will get overturned — and not by a 5-4 vote.

Alito closed the loop on the question:

Justice Sam Alito asked Verrilli whether he could point to another case in which courts identified something as not a tax for the purposes of the Anti-Injunction Act while still ruling it was a constitutional exercise of taxing power. Verrilli could not name any.

That doesn’t bode well for ObamaCare advocates.  If the mandate gets struck as a constitutional overreach, then regardless of whether the Supreme Court finds severability or not, the entire structure of ObamaCare collapses.  It will hasten momentum for its repeal, and insurers will switch sides to demand its complete rejection.

I’d tell you to watch for more signals, but of course, you can’t.  The Supreme Court rejected requests to televise arguments today, but two polls show that Americans overwhelmingly think that the proceedings should be viewable.  USA Today/Gallup shows that 72% want the arguments televised, including 70%+ among Republicans, Democrats, and independents.  C-SPAN, which would have been the likely broadcaster for such an event, has a poll showing 74% support for televised hearings — and 95% who want the Supreme Court to be more transparent in its proceedings in general.