[School of Rational Thought]

The power to take any action that has a negative impact on ithe other states are also denied to the states. They cannot lay imports on the goods of other states, cannot enter into leagues against them cannot declare war against them or refuse to recognize their public acts. They cannot deny citizens of one state the rights their own citizens have. They cannot refuse to extradite fugitives. Given these kinds of actions are denied the states, then by implication unilateral secession and the negative impact it had on the remaining states is a power denied as well. Except in matters of the second amendment? Queer marriage? Illegal immigration?

[Non-Sequitur]

Except in matters of the second amendment?

A state cannot force its actions on another state. Kansas has one set of concealed carry laws, Missouri has another. A Kansas citizen cannot go into Missouri and demand a permit if they do not meet Missouri requirements merely because they have a Kansas permit. Likewise a Kansas citizen cannot carry in a state that forbids concealed carry merely because they can in Kansas. A state's laws cannot carry over the border unless the other state permits it.

Queer marriage?

In Kansas the state Constitution defines marriage as between a man and a woman. A homosexual couple cannot come into the state and file as a married couple, state law forbids it and just because Massachusetts says that they're married does not make them so here. An action that is legal in one state is not automatically legal in another. Nevada has legalized prostitution, that doesn't mean hookers are free to do so here.

Illegal immigration?

Last time I checked illegal immigration was a federal matter, not a state one. Illegal immigration?