I'll respond to the little bit of your post that isn't a baseless ad hominem.
Presidential pardons have legal validity for purposes of righting wrongdoings, travesties of justice, and for preventing excessive punishment of those unjustly sentenced for political crimes, etc. It's stated intent is to correct injustice, not perpetrate it.
I'm not suggesting that every enemy combatant deserves trial -- in an active war, it is ridiculous to suggest that bullets are halted mid-air to conduct court. It is equally naive to suggest that the government is justified in the slaughter of everyone who might ever do us harm.
Has it been abused, certainly. Show me a law that hasn't. The difference between pardon and NDAA-type of laws is that the latter has no redeeming characteristic. Its sole purpose is to vest a single person with the power to do literally whatever he wishes, without oversight, without scrutiny, without potential for remediation. There is no justice to be found in its exertion, even when used for noble intent.
There are, or at least were, procedures in place that would have prevented such atrocity from occurring, but those procedures were nullified by the NDAA. There is no need for government oversight whatsoever, nor any reason to suggest that whomever happens to be president cannot simply murder whomever he wants under the guise of national interest.
I understand that the NDAA and PATRIOT Act weren't created in a bubble, but as you have implored me to "study the history" (which I am well aware of, and don't understand what I might have said to convince you of my ignorance of an era that I was actively involved in), I would implore you to study the documents that led up to our nation's independence.
Overwhelmingly, they point to the foulness of this sort of unchecked power, and the founding fathers literally made every effort to ensure that this sort of abuse never came to pass.
Whether or not the NDAA or PATRIOT Act is ever used is irrelevant, their very existence negates the tenets of our central foundation of governance.
> Sometimes the US government goes too far, but not nearly as often, or nearly as extreme as you keep saying
The federal government goes beyond its Constitutional authority literally every single day in this nation. The government exerts federal control in California to arrest the proprietors of legal marijuana dispensaries. They do this by abusing the Interstate Commerce Clause. The Commerce Clause grants Congress the power "To regulate Commerce with foreign Nations, and among the several States, and with the Indian tribes" -- and by abusing the 'among', have defined that to mean that they can control any action within a state, whether or not that action may extend beyond a state's borders.
The federal government further abuses the 'Necessary and Proper' clause to extend its powers beyond their section 8 enumerated powers.
There are literally countless examples of federal overreach, some of which are gaining ground in recent times, like the overturning of DOMA (Thanks Obama). I'm sorry you don't see them, or don't see them as the overreach I so strongly believe them to be.
Either way, I won't further engage in a conversation predicated on your baseless attacks due to a relatively minor disagreement on merits. I would encourage you to learn how to converse with others without resorting to ad hominem attacks. Your views aren't invalid just because I disagree with them, however strongly I might, and you'd do well to acknowledge as much.