[2] The same protocol was adopted by the US Coast Guard when it was established as a military service in its current form and title in the early 1900s.

The new rank of commodore admiral was created both as a means to appease the other three branches of the U.S. military, who felt that promoting USN and USCG O-6s to O-7, yet entitling them to wear the insignia of an O-8, was unfair, and also as a means of distinguishing that Navy and Coast Guard one-star admirals were in fact flag officers.

This had been a major problem in World War II, when cultural mistakes had led to several US Navy commodores being regarded as senior captains by members of foreign militaries and in turn denied honors due to a U.S. flag officer.

However, this change caused even further problems internal to the Navy because senior captains commanding multiple units, e.g., those in charge of air wings and air groups, destroyer squadrons, submarine squadrons, etc., had held the honorary title of "commodore" for decades.

It was replaced by the new rank of rear admiral (lower half), essentially the same title as before dating back to before World War II.