I mean it would be the Law of the Land. I wouldn't agree with it, just like I don't agree with other laws, but that doesn't mean I wouldn't support its enforcement.
In an accessible safe.
Ehh kinda, the original intent of the 14th Amendment almost certainly was never intended to apply to marriage equality (but it kinda sorta could if you squinted hard enough; deliberately vague language to apply to unforeseeable future circumstances and all that). With the case of the gun regulation, there is far far less flexibility. But then again the Commerce Clause was never meant to be used to force desegregation of private businesses and yet you had the Civil Rights Act of 1964 upheld. So yes there are cases where the Supreme Court will twist itself into a doctrinal pretzel to get out the outcome it desires, but really only does so in practice when the compelling moral/public interest/consensus is so undeniable that to rule otherwise would seriously damage the integrity/legitimacy of the Court itself in the public eye.
tl;dr: The court won't let Obama get away with any sort of significant Executive overreach on gun control