In the USA, unless they have a contract, you can definitely fire someone for being an asshole. If you have any sense whatsoever, you'll simply say "we've decid

In the USA, unless they have a contract, you can definitely fire someone for being an asshole. If you have any sense whatsoever, you'll simply say "we've decided not to continue your employment" and offer them a month of paid COBRA and two weeks of pay in exchange for an agreement not to sue.