Really Professor? I must say, firing is hardly the appropriate response. If we hadn't become such a bunch of limp wristed sissies, we'd recognize that we already have the appropriate, perfectly legal response:
"18 USC 2381. Treason
Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States."