There is a big twist to this.
The SCOTUS has in past recognized that state courts are inferior to federal courts; and that state legislatures are inferior to congress; however, they have *never* found that the POTUS is superior to state governors.
This means that the only way the president can enforce his will over that of state governors is by force of arms.
The last time this was done was when Eisenhower sent the 101st Airborne into Little Rock to force integration, despite the presence of the Arkansas National Guard, under the orders of governor Orval Faubus.
The trick, in this case, would be to arrange a similar situation, figuring that the current administration is too spineless to send in the Army to enforce an unconstitutional law.
Granted, all else being equal, the feds would eventually win. But the purpose of the exercise would be to so thoroughly embarrass them, and rally so much opposition to them, that they would lose the game.
This is not really a POTUS versus a state governor legal issue. Basically, Holder is saying that Kansas law enforcement cannot lawfully arrest federal agents performing federal duties even with the Kansas state statute. The authority that federal law enforcement agencies fall under is actually a result of Congressional law. In other words the law enforcement power and various jurisdictions of federal law enforcement agencies is granted and defined through federal law. Basically Holder and of course the POTUS ultimately administers these federal law enforcement agencies but their actual authority to carry out federal law comes from the legislative branch of Congress.