Well, it's more specifically refusing to submit to an unconstitutional ruling. (There are laws that could be found constitutional that some may consider unjust, but the standard for federal law is the Constitution.)
The issue almost certainly will be money - federal funding. It's basically a dependency issue. We're back where we were 250 years ago - the issue of breaking free from dependency on an oppressive, unjust government. States that have the guts to stand up to the feds also need the guts to go it alone financially. That is not such a bad thing necessarily. If that state understood the need for small government, low taxes, and the value of the free market economy, it could soon be more financially sound than the bankrupt federal government.
Arizona has already passed a law allowing the state to reject unconstitutional federal acts. But just like it was way back when, it comes down to money and politics versus principle and freedom. Where's the band of freedom lovers who are willing to risk "life, fortune, and sacred honor" for freedom? Ultimately, again like at our beginnings, it will be God's miracle to raise up such a band and make it happen.
It would be toughest for states with no ocean harbors, but it seems the way the gov. has worked then succession would be at a severe $ cost, but is it even constitutional?