Deploying Army on US soil

this is a genuine question from France, so please I am really worried (and if dear moderators feels so, please move this post to a more adapted spot)

My questions are, as Trump threathen to deploy US soldiers against riots :

  1. Can the federal army be used on US soil?
  2. can the federal army be used against US citizens?
  3. can the president overrule the states on security questions?

To provide a context, in France, the military has no power to arrest citizens (except on army bases wich are not authorized to civilians), and when deployed for security purposes (patrols in railway stations, around cult places, schools,… during the Sentinel opérations) it is with an accompagning and commanding police officer who will handle the legal stuff, the militaries are only here to provide immediate heavy fire support against a terrorrist attack.

Apparently yes. But in extraordinary circumstances. Hopefully, Wikipedia is acceptable for this question.

There is the POsse Comitatus Act and the Inssurection Act. They are at odds with each other as to what the federal government can do in this regard.

That usually means the president can do whatever he wants and later claim no one could say it was clear he couldn’t.

On the face of it, that Wikipedia link

seems pretty clear that the President of the US can freely use the military against US citizens and on US soil as he or she sees fit. Doesn’t seem it would be run past a judge first.

It mentions “enforcing… laws”, though; it’s not clear that means the military can arrest people and run them through courts martiales (as in true martial law), so this use of the military is not obviously different from the “heavy fire support” role in France, at least not based on that particular text. Unless “impracticable to enforce the laws of the United States… by the ordinary course of judicial proceedings” really does mean the President can declare martial law whenever he or she wants.

When two laws contradict each other, the one passed last (in this case, the Posse Comitatus Act) supercedes the other. At least that’s my understanding and I don’t know why it would be different. But perhaps there’s some case where this does not happen.

They don’t contradict each other; the Posse Comitatus Act (which consists of only one provision and can thus be easily cited in full) says:

(Bolding mine).

The Insurrection Act is an Act of Congress that authorizes the use of the armed forces to execute laws, and is therefore exactly the kind of exception the Posse Comitatus Act accepts.

The bigger question is why, legislatively, both acts remain on the statute book - one of them prohibits something, but subject to exceptions duly provided for by the other. I suppose this is done to emphasise the extraordinary and exceptional nature of using the armed forces in such a way.

IANAL, but Governors have some power to call out National Guard. (Or is this a request that has to be approved by White House?) If a Governor has already called out the National Guard (with the Guard presumably reporting to Governor, not Pentagon) that might not legally prevent Trump from sending his own Army, but it would render such a move obviously hostile.

When the Little Rock Nine were to be integrated into the all white school, the Arkansas governor called out the National Guard then Eisenhower federalized the units.

Absent any action from the federal government, the state governments can use their National Guard* units however they choose, subject only to whatever limits the state constitution and/or laws have imposed. The White House could supersede them, but the state doesn’t need any sort of federal authorization beforehand.

*It might not be obvious from the name to a foreigner, but the “National Guard” is a set of state-level military forces, sometimes referred to as the militias of the states. They can be called up by the federal government, which usually only happens in times of war, but until and unless they are, they’re under state control.


I think it’s more to clarify that the military isn’t to be used for garden-variety law enforcement purposes, but is available for rebellions and insurrections like the Civil War.

That’s where, I’d think Trump’s threat falls down- it’s going to be a pretty big stretch to claim that there’s any sort of insurrection or rebellion going on, if neither the cities nor the states believe there is and aren’t asking for Federal help.

It comes down to him saying that the states can’t handle it, and that’s why he’s sending in Federal troops, and making that stick.

I am sorry, but what? The Insurrection Act has been employed several time post Posse Comitatus
Including for much lesser public disorder cases, including over the states wishes.

Stick how, though? Whom does he have to convince?

Federal courts, judges, etc… I’m pretty sure they could all issue stays to prevent him from deploying troops in violation of the Posse Comitatus Act.

True. But if you read the text of the Insurrection Act, you will find provisions such as:


(Bolding mine.)

This is the type of wording that is typically used in statues to indicate discretion, and accepted by courts as such. In other words: With this statutory wording, it’s likely - not certain, yes, but likely in light of the usual methods of statutory interpretation - that courts would accept that an “insurrection” within the meaning of these provisions exists when the President says there is. Unless the invocation of the provision is clearly and evidently abusive and it is plain to see that no “insurrection” is taking place. Which, considering what is going on and in which precedents the Act has been used before, is probably not the case. This may sound provocative considering how controversial the current President’s administration is, but once you disconnect the debate from his person it really is not that unusual that in some matters, the President does enjoy a wide range of discretion.

Invocation of the Insurrection Act is likely to be judicially non-justiciable under the “political questions” doctrine.

I do sopmetimes wonder if Ancient Romans observers of Sulla were like Americans now, there is no way in hell he can do that, followed shortly bydamn he did?

The other question, obviously - are the military allowed to enforce state laws without the consent of the governor, or just federal laws? They can, from what’s posted, enforce the laws of the Federal Government. they can take measures to combat domestic violence, assembly or conspiracy that “hinders the execution of laws” but they cannot actively enforce state laws? Is there a federal law against looting or arson in a state?

Well, thanks for the replies. My mind is cleared.