There is no power in the laws or Constitution to coerce a state. However, the Militia Act of 1792 gives the president the power to put down insurrection. The Supreme Court ruled in 1862 that he was properly applying this power and this opinion is present in both the majority and dissenting opinions in The Prize Cases.
Walt
The Militia Act does not apply to a state that seceded, even though the central government or a sectional party aggrandizing itself at the expense of other states might assert that it does.
What about New York and Virginia's conditions on ratification of the Constitution that they could resume government again if they wished? I imagine the Federalists knew they could never get the Constitution ratified if they included a "thou shalt not secede" clause in the Constitution. They would have lost New York, Virginia, and I forget who the third state was that expressed similar conditions.