And the Supreme Court doesn't have an obligation to take up any cases at all -- if a law is clearly unconstitutional, presumably the lower courts will strike it down.
Yes, I agree that if the lower courts overturn the law, and the challenge continues to the Supreme Court, the court might very well refuse to hear the case. No harm, no foul.
If however, the law isn't overturned and gets to the Supreme Court, it seems that there would be incredible pressure on the justices to hear the case since it's in direct violation of federal laws. Given the visibility and national importance, is it really likely that they would just refuse the case and ignore what SD is doing? Wouldn't that be a very risky approach and invite other states to do the same? It would also seriously damage the credibility of the court with most Americans. Maybe one of the lawyers can chime in with some historical precident where the court has declined cases where state laws reversed federal laws.
Part of me wants this to go down just so I can see what happens. It would be ironic for the court to refuse to hear a state challenge to one of the most controversial laws in US history, but would hear a case about a drugged up stripper who is fighting for billions because she blew a 90 year old guy a couple of times.