Demoting him?
Milley committed acts of espionage, sedition and treason.
He should be indicted and tried for these capital offenses.
Easy to do, recall him to active duty and court marshal him. The pre-emptive pardon he received would not protect him there.
This is firing squad territory.
“Demoting him?”
A general losing a star is reason enough for them to eat their service weapon. It removes their dignity and is the ultimate insult. No need to try them in a court of law. Demotion is enough.
As a military retiree, Milley is already subject to military law:
https://crsreports.congress.gov/product/pdf/LSB/LSB10945
The Supreme Court has not yet specifically ruled on the military status of retired servicemembers, though it has approvingly noted that they remain part of the Armed Forces and subject to the UCMJ. Federal appellate courts (e.g., the U.S. Court of Appeals for the District of Columbia and U.S. Court of Appeals for the Armed Forces [CAAF]), however, have consistently held that military retirees possess a military status that makes them subject to military law. In finding such status, courts have highlighted several connections between retired servicemembers and the military: they can be recalled to active duty and, accordingly, serve as a potential source of supplementary personnel; they are entitled to receive special pay and other benefits from the military, which are viewed, at least in part, as retainer conferrals; and they have the right to wear their uniforms and be referred to according to their rank (in certain circumstances).
The U.S. Court of Military Appeals (now the CAAF) articulated a widely adopted position in 1958 in United States v. Hooper: [Those] on the retired list are not mere pensioners in any sense of the word. They form a vital segment of our national defense for their experience and mature judgment are relied upon heavily in times of emergency. The salaries they receive are not solely recompense for past services, but a means devised by Congress to assure their availability and preparedness in future contingencies. This preparedness depends as much upon their continued responsiveness to discipline as upon their continued state of physical health. Certainly, one who is authorized to wear the uniform of his country, to use the title of his grade, who is looked upon as a model of the military way of life, and who receives a salary to assure his availability, is a part of the land or naval forces.
If you’re going to bang your drum constantly on a subject, it would add greatly to your position if you spelled your central point correctly: court MARTIAL.