It's a quick reaction, but both the upholding of the legality of PCAOB in the Free Enterprise case and the mandate in this case suggests that although this is a Court that worries - possibly excessively - about structural niceties, a serious outlawing of a major government program is something that will be ventured very, very rarely. Some critics, including yours truly, think that this is one of the reasons why the obsession of some legal scholars with constitutional law, given its limited bite, is so strange.
Count me among those who also find it more than a bit odd.