Eh, it's way past my bedtime, and I really need to sleep, but what the hell, I'll give it a shot as the Devil's advocate.
The issue:
I can see two main developments that has led to the situation turning out like this, and two possible choices ahead. One of those choices is that "the President of the United States asserting the power to issue kill orders for U.S. citizens without any judicial process". I'll come to the other.
The first development you have already touched upon:In todays world - well from the beginning of this millennium - military action and police action has become intermingled, and the difference between capturing a heavily armed criminal and fighting a war against a country is on its way to being eradicated.
Bounty hunters, secret agents, weapons depots, kidnappers, police, battlefields, terrorists, drug lords, corporate warriors, huge state armies, smugglers, extremists of all kinds, rebels and hit men seem to all have been mixed together into the same madness.
As such, it seems more and more evident that police will need military abilities and the military will need police abilities, and we will be losing the notion of having the police maintain security inside the state, and the military maintain security outside the state.
The second development is that the world is becoming more and more globalised. Migration becomes easier, trade and communication goes all over the world at all times, and multicultural societies become more and more the norm. Because of this notions such as American (US citisen), Norwegian, Mexican, Iranian, Egyptian and whatever else becomes less and less useful as labels that say anything at all about the people bearing them.
These two developments together means that if a person has a US citisenship, but resides in Yemen and actively fights the US, there is little to distinguish him in any real way from a person having some other citisenship, residing anywhere and fighting the US, since a Muslim Afghan may just as well live in the US as in Afghanistan, or in Yemen, etc.
If you insist that the President of the United States can not take the life of a person holding a US citisenship without the permission from a US court, then, by extension, the President of the United States may also not take the life of any other person without permission from a US court. Imagine, if you will, that the Taliban is a bit stronger, and has an armoured division being led by a guy with a US citisenship. Would the President need a US court to give permission before he can give orders to fight this division and kill/capture this guy? What if there were a thousand US citisens in the ranks of a well-armed Taliban military?
Of course, for fighting a war such a requirement would be absolutely disastrous. It would bring any advance a US military force could make to a screeching halt every time they needed to get a new permission from a court.
Or could they simply get an extended permission to fight until the war was over? But what then would hinder the President from ordering the killing of this person in Yemen? Or the killing of a US citisen anywhere, even inside US territory?
The two possible choices seem to be to insist the the President needs a court's permission every time he wish to kill/kill-if-can't-capture a US citisen, or to accept that the President does not need a court's permission to kill at all.
/Devil's advocate.
What do you think? Was I able to put together a logical argument at all, or is it just a big piece of rambling? And does it make sense?![]()
Not bad.

We shoot criminals that are citizens practically every day in this nation in trying to apprehend them. And the more dangerous the criminal, the more likely the use of deadly force being used. I dont really see the difference here.
Perhaps you can't see any because there are too many to list. E.g., (i) "trying to apprehend," (ii) a misunderstanding of the police justification for the use of force, (iii) process after the shooting, (iv) the secret nature of the assassination program, &c.
Cleo