SCOTUSBlog:

The Court will hold two hours of argument on the constitutionality of the requirement that virtually every American obtain health insurance by 2014, 90 minutes on whether some or all of the overall law must fail if the mandate is struck down, one hour on whether the Anti-Injunction Act bars some or all of the challenges to the insurance mandate, and one hour on the constitutionality of the expansion of the Medicaid program for the poor and disabled. The Court chose those issues from appeals by the federal government, by 26 states, and by a business trade group. It opted not to review the challenges to new health care coverage requirements for public and private employers. It left untouched petitions by a conservative advocacy group, the Thomas More Law Center, and three of its members, and by Liberty University and two of its employees.

As SCOTUSblog notes later in the post, five and a half hours for oral arguments is unprecedented. Arguments on Citizens United were four hours long. It's clear the court realizes the importance of the questions before it, though not all questions are being considered.

Overall, it appears that the court has chosen to consider the Affordable Care Act in the context of the interstate commerce clause and states' rights, which frames not only the arguments over health care, but sharp differences between conservatives and liberals about the role of government in individuals' lives as well as individual states.

SCOTUSBlog:

Beyond the Court, there is a hot political debate going on across the country now on federal vs. state power, and the Court’s coming decision is likely to become an issue in that debate — especially since the final ruling is expected to emerge from the Court in June, in the midst of this year’s presidential and congressional election campaign.

From a political standpoint, it would appear that a ruling striking down the individual mandate would certainly energize a movement to move to a single payer model for everyone or at the very least, a public option, given that insurers would be bound to not exclude or charge exhorbitant rates for individuals with pre-existing conditions. If there is no individual mandate, it's likely that insurance would become unaffordable for everyone because of the adverse selection issues. If they uphold it, 2012 becomes even higher-stakes poker for conservatives, who will try to retake the House, Senate and White House to repeal the entire law.

As Ezra Klein notes in the video, it is possible they could simply say no one has standing to bring a case until the law is actually effective, too. If they were to do that, it would set up a situation where the provisions of the law become more popular as they become effective, which would make it more difficult for conservatives to repeal or limit it.

I will update this with more analysis as it's available.