Yes he can, but since he fired Comey after Comey failed to break the law at his request I guess it was an order after all!
Once again, the cover-up is far worse than the original crime. If he hadn't fired Comey, then it would have just been "a favor". Trump made it an impeachable High Crime, but that's not too surprising. The list is as long as your arm and it's all stupid decisions by Trump. There's a reason why Presidents often have legal training.
