Are There Five Votes to Uphold ObamaCare's Mandate?

Tom Goldstein of SCOTUSblog has a brief mid-argument update from inside today's Supreme Court hearing over the constitutionality of ObamaCare's health insurance mandate:

It is essentially clear that the four more liberal members of the Court will vote in favor of the mandate. But there is no fifth vote yet. The conservatives all express skepticism, some significant. They doubt that there is any limiting principle.

At the time of Goldstein's post, the challengers had yet to argue, so things could change quickly. We'll know more soon enough. 

Update: Justice Anthony Kennedy, believed by many to be the crucial swing vote in determining the mandate's constitutionality, said the government faces a "very heavy burden of justification" to show how the Constitution would authorize the mandate, according to The Wall Street Journal.