Thanks for the info about the AUMF. I'll definitely have to look into that further.

Notice that the 2001 AUMF, which was written in a panic,
authorizes arbitrary force with no mitigating effort
required not only against nations but against
"organizations" and "persons", and continues to authorize
those efforts so long as they might prevent future acts of
terrorism.

It is hard to get much worse than that. The NDAA doesn't
make it worse; in fact, by putting pen to paper and
outlining specific circumstances in which the US can use
its military to detain people, it ostensibly makes it
better (it is hard to imagine making the 2001 or 2003
AUMF better without repealing it and starting over,
though).

Yea, that's definitely horrendous. That being said, the entire purpose of Section 1021 of the NDAA 2012 is to affirm those governmental powers. There's even a section which I cited which specifically states that the NDAA doesn't limit the President's powers at all: "(d) CONSTRUCTION.—Nothing in this section is intended to limit or expand the authority of the President or the scope of the Authorization for Use of Military Force." Which basically means "everything we just said about limits and expansions means jack squat when it comes to the president; (s)he can do whatever". So yea, the AUMF started this, and it was broad and allowed everything. The NDAA is still a problem because it continues it and doesn't actually limit anything when it comes to the President.

The Alex Jones take on the NDAA would be that it's a huge
executive overreach and a sign that the current
administration favors an overt authorization of Latin
American-style "disappearings" of suspected terrorists.
Apart from the 2001-2003 context those febrile rants
exclude, there is also the fact that the House and Senate
GOP wanted the 2012 NDAA to expand the powers available
to the executive to combat terrorism.

I don't think I mentioned Alex Jones. Also "huge executive overreach and a sign that the current administration" and "the House and Senate GOP wanted the 2012 NDAA to expand the powers available to the executive". Both of those are right :) Both parties are responsible for this. This is a bi-partisan effort haha.

It is also possible to be disquieted by detention and due
process provisions in a war powers act while
simultaneously understanding the context in which a
reasonable person could assert them. For example,
without some provision for detaining US citizens abroad,
how would you lawfully handle any armed conflict with
the Taliban? There are more than 300MM Americans. Some
of them will win the lottery, and others will in fact
fly to Pakistan to train with militants, as has already
happened repeatedly. US military forces will eventually
encounter them in armed conflict. In every war, there
is always going to some due process concern regarding
the handling of possible US citizens taking up arms to
fight alongside our opponents.

If a US citizen is engaging in a firefight with US armed forces, then yes, there's your proof they are "terrorists". If you can a US citizen in the act of building a bomb, then yes, there's your proof. However, if through the grape vine you gain "intelligence" that a certain US citizen is a "terrorist", by constitutional law you must provide that citizen a fair trial by a jury of their peers (i.e. not a military trial). If overseas, bring them back to the US. The AUMF generally and NDAA more specifically do away with that requirement (which is, in my opinion, one of the most fundamental aspects of american freedom).

The Al Qaeda AUMF is ridiculously overbroad and needs to
be fixed. But the NDAA, a utility bill that happens every
year to fund the military, is not a re-ratification of
that act, nor does it create a civil liberties regime
in the US comparable to that of China.

If it's not a re-ratification, then why mention it? If the government doesn't need it, why put the language in there? I think it's important to keep in mind that few things are put into legal documentation without express purpose, especially at the level of government.