It sounds like the AFL-CIO thugs want The One to expel states from the Union. They're sure he can find the power somewhere.
While he's at it, maybe this would be a good testing ground for his "heavily armed civilian defense force" as he pulls out the Border Patrol, FBI, ICE, TSA, and all those other federal agencies. They'd avoid the border, because there's no real problem with the border, except for Arizonans.
The Brown Shirts would be able to continue collecting taxes after the IRS is pulled out since they are, after all, heavily armed. They just need representation by the AFL-CIO and they'll be ready to roll.
Not expel. Intervene.
Article IV, Section 4: The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence.
Back in 1964, black civil rights leaders asked Lyndon Johnson to invoke Article IV, Section 4 to execute a federal military takeover of the southern states due to the semi-official state terrorism of black folks run by the Klan. (It was hard to tell where local law enforcement ended and the Klan began in much of the South.) With a presidential election just months away, Johnson decided not to open that can of worms. He told the civil rights leaders the Constitution didn't give him that authority, even though it did.
The double-edged sword in Article IV, Section 4 is "shall protect each of them against invasion," which is exactly what is happening, although in this case the invasion is endorsed by both parties in DC for different reasons. It might be tempting for Obama to invoke Article IV, Section 4 against Arizona, but those words would blow up in his face if he tried.