It is, I believe, significant that the Kansas governor has signed law in that state nullifying federal gun laws, even future ones, that are inconsistent with the original understanding of the 2nd Amendment.

As the article states:

  "The language and act of nullification goes back to "The Nullification Crisis" in the early 1830s, when South Carolina told the federal government the ultimate arbiter of what is and isn't constitutional is the people. The state argued that the people are clearly identified with the state in which they live, per the 10th Amendment of the constitution.

The language and appeal to a compact between a state and the federal government goes back to Thomas Jefferson's writings in the Kentucky and Virginia Resolutions. There he argued that states form a compact with the federal government whereby they delegate powers to the federal government but are at liberty to recall those powers if the federal government abuses them. 

Concerning guns and gun laws, Kansas is nullifying future laws and recalling the power it had granted to the government in this area because it believes the government has been abusing the people's rights in regards the 2nd Amendment. "

That sort of argument is part of what got us into the Civil War.  In addition, the rubber will meet the road when Kansas actually does something to physically stop the feds from enforcing the law, at which point the litigation stream to the Supreme Court will initiate.

What happens if the Supreme Court says Kansas can't do that, but Kansas says it will anyway, will be the real crux of the problem.

I suspect that the governor here is signing the law knowing it is politically popular in his state, but knowing at the same time that it will take several years to litigate the issue to it's conclusion.   Then, he can back off, claiming that he rightly must obey the Supreme Court on this.  

So, I don't know if this law is anything more than a paper challenge to the power of the Federal Government, or if it is real.   Time will tell, buy my money is on a paper challenge.  To defy the Supreme Court would really require the people to pull out their guns and then challenge the Feds to fight.  I don't really know if the American people have that in them anymore.