This should be an interesting debate. Under the law, is the national guard allowed to shoot people who are looting target? President Trump that looters will be shot.
(Please cite the relevant law when answering the question. Thanks).
Perhaps there are variations by state, but in Minnesota, deadly force when applied to protecting property appears requiring meeting a national security standard:
https://www.govinfo.gov/content/pkg/CFR-2017-title32-vol4/xml/CFR-2017-title32-vol4-part632.xml
 "632.4Deadly force.(a) Deadly force is destructive physical force directed against a person or persons (e.g., firing a lethal weapon). Use it only in extreme need, when all lesser means have failed or cannot reasonably be used.
"Use deadly force for one or more of the following reasons only

1) In self-defense, when in imminent danger of death or serious injury.(2)
"To protect property related to national security, when reasonably necessary to prevent—(i)
"Threatened theft, damage, or espionage aimed at property or information specified by a commander or other competent authority as vital to national security. (See paragraph (b) of this section.)(ii)
"Actual theft, damage, or espionage aimed at property or information which, though not vital, is substantially important to national security. (See paragraph (b) of this section.)"