Adam Serwer bets that the tax/penalty distinction won't delay the ruling:

The justices seemed clear that they would not duck the historical moment by avoiding a ruling on Obamacare under what might be called a tax dodge. Judging by their remarks, the Obama administration is likely to see a verdict on its signature domestic program prior to the November election. But there's still no telling what that verdict might be.

Patrick Caldwell nods:

It's not too surprising to see the court tracking this way. Neither the plaintiffs nor the defendants thought the Anti-Injunction Act was relevant to the case, so the Supreme Court had to hire an outside attorney, Robert Long, to air the case. Obama's Solicitor General Donald B. Verilli Jr. in fact argued before the court Monday that the justices shouldn't read the individual mandate as a tax in this sense, a clear sign that the administration thinks the court is on its side and wants to dispatch with the constitutionality questions before the president's reelection campaign this fall.

Ilya Somin adds some caveats:

First, the justices sometimes ask questions for rhetorical effect or play devil’s advocate. I don’t think they are doing so here, but obviously I can’t be sure. Second, it is theoretically possible that the constitutional definition of what qualifies as a “tax” is broader than the [Anti-Injunction Act] definition. 

Jeffrey Toobin isn't predicting anything but worries about a court radical enough to decide Citizens United: