“If someone is an enemy combatant they have to be in combat or have been in combat against US Forces.”
Okay, what is your definition of combat? If you limit it to just those Americans actively throwing bullets at our soldiers, then those Americans are almost unimportant to the enemy. There is almost nothing they could do that some illiterate goat herder couldn’t do, unless the American had special military training from a modern military.
However, if they are advising enemy leaders, giving them useful information on how to attack American citizens in America, how to build bombs, how to hide their communications, what foreign leaders to assassinate, etc., they are a major threat. They might not ever fire a shot at an American, but be responsible for the deaths of thousands of Americans.
And these latter group are Americans who have been targeted in drone strikes. They are enemy combatants in a rear area of the FATA in Pakistan, where they cannot be arrested, are not under the control of any government, and are invariably with high level enemy leaders planning operations against both our military and our civilians when they are killed.
This is a very restrictive license to kill American citizens; because almost anywhere else in the world, outside of Somalia or the Maghreb region of northwest Africa, either the US has the *ability* to effect arrest, or at least there is a government that can compel an errant American to stop making war on America, or give aid and comfort to our enemies.
In all but these circumstances, such drone strikes are unwarranted.
The strikes were in Yemen so there is no reason not to apprehend the citizens. Also our own government helped train Osama Bin Laden and he has used the knowledge to train others to kill us. Can we just kill the ones who did this, no we must follow the law.
Allowing the government to ignore the law once just leads to more injustices down the road. That is why we have cops that can kill people and animals in botched raids here in the US. The government is not following the Constitution and we the citizens are paying for it.