Oh well, I missed some fun.

Just to be clear, arresting the President to relieve him of his duties as Commander in Chief would clearly be unconstitutional; and using the military to unconstitutionally change the government is what's called a "coup d'etat." There's no arguing around this.

Why would it be unconstitutional? Because the Constitution itself makes the President Commander in Chief. Any Commander in Chief set up by the military that wasn't the President would be an unconstitutional Commander in Chief.

The best part, of course, is that if the military were to arrest the President (even put him under, say house arrest -- "Hard-liners in the Soviet leadership, calling themselves the 'State Emergency Committee', launched the August Coup in 1991 in an attempt to remove Gorbachev from power and prevent the signing of the new union treaty. During this time, Gorbachev spent three days ... under house arrest at a dacha in the Crimea before being freed and restored to power."), the new military overlords wouldn't likely be political liberals. I can't understand how Martin Lewis and the Huffington Post don't realize that detail.