Section 1031 is on page 426
Subtitle D—Detainee Matters
SEC. 1031. AFFIRMATION OF AUTHORITY OF THE ARMED
17 FORCES OF THE UNITED STATES TO DETAIN
18 COVERED PERSONS PURSUANT TO THE AU-
19 THORIZATION FOR USE OF MILITARY FORCE.
On page 428 it states
10 (e) AUTHORITIES.—Nothing in this section shall be
11 construed to affect existing law or authorities, relating to
12 the detention of United States citizens, lawful resident
13 aliens of the United States or any other persons who are
14 captured or arrested in the United States.
See? Nothing to detain US citizens, legal aliens or anyone captured in the US.