I believe you mean precedent. I dunno. What would George Washington’s army have done with a colonist who joined the redcoat army? I suppose, capture if possible and subject to military trial. If that was infeasible, then a direct attack as on an enemy would be expected.
American born Abdulrahman Al-Awlaki had no ties to terrorist organizations but was targeted and kill without any evidence or due process. This is using national resources to commit murder without any oversight.