Currently, over 20 state attorney generals, all Republicans, are suing the federal government to overturn Obamacare. Now 10 state attorney generals , all Democrats, are writing a letter (in legal terms it's called an "amicus brief") to the Supreme Court defending Obamacare.
It is an interesting glimpse into the psyche of American legal scholars who presumably study the same constitution, yet they can come to very different conclusions. Justice Scalia once said that his rulings, and the rulings of the Supreme Court in general, are not made based on personal opinion, but rather on the constitutionality of the arguments. Scalia's argument is plausible when you consider the recent ruling by the Supreme Court to allow the Westboro Baptist Church to continue protesting at funerals.
However, one wonders how possible it is to separate personal opinion from Constitutional interpretation. With scholars lining up along partisan lines, it seems unlikely that the Justices of the Supreme Court will not rule mostly along partisan lines. I am not prognosticator, but I predict Obamacare being declared constitutional by a slim majority, with all the liberall justices voting in favor, and one or two centrist judges upholding the law as well.