As conservatives cry about Chief Justice Roberts being a traitor, or having suffered an acute bout of confusion because he has epilepsy (yes, seriously), a 2007 article by Jeffrey Rosen — Roberts’s Rules — provides some much-needed context for Roberts’s actions.
In Roberts’s view, the most successful chief justices help their colleagues speak with one voice. Unanimous, or nearly unanimous, decisions are hard to overturn and contribute to the stability of the law and the continuity of the Court; by contrast, closely divided, 5–4 decisions make it harder for the public to respect the Court as an impartial institution that transcends partisan politics.
With the above in mind and after reading the opinion carefully (some parts, more than once), I think that Roberts’s approach was outcome determinative and ultimately, very savvy. He threaded the needle in such a way that he could find the mandate constitutional without advocating for what he saw as such an overexpansive interpretation of Congress’s power to regulate interstate commerce under the Commerce Clause that it rendered such power almost limitless.
(There’s a whole lot more at ABLC.)