Not arrested. Detained. It’s authorized by the NDAA. Does the NDAA exclude the executive branch from among those who can be detained? Does it require the CINC to sign off if, for instance, they wanted to come knocking on my door and haul me away for being “belligerent”?
The logic you’re using would say that no police chief could be arrested if one of the guys under him caught him murdering somebody. I don’t buy it. In fact, I believe that the 14th Amendment speaks loudly against that. The law is NOT to be a respecter of persons but is to treat all equally, and having a political office does not make one exempt from the law - especially not when it regards what Congress (the body authorized by the Constitution) has decreed regarding the making of war and of national defense when asymmetric warfare is the warfare used against us.
Unless I’m quite confused, the military is prohibited by posse comitatus, and probably other laws, from performing law enforcement in the United States, except under very specific exceptions.
Do you really, seriously want to set a precedent for the military to remove presidents from office?