Because "official actions" doesn't mean "every action" or "every action attempting to use presidential authority," I think it has to be an action exercising the constitutional powers of the president.

For instance: for the purposes of simplicity, lets assume all legislation authorizing the president to take military action without prior congressional approval has been repealed, and the congress has not declared war on anyone or authorized the use of military force in any circumstances. The president then orders Seal Team 6 to assassinate a waitress who spilled coffee on him, ruining his lucky suit. That would be illegal order since the president does not have constitutional authority to take such action on his own without authorization by congress and that authorization does not exist.