Coast Guard is a uniformed military service, they just aren't part of the Department of Defense. I would not use the word subordinated to the Navy; they can become "part" of the Navy during conflicts. For example the Coast Guard had units attached/assigned to the Navy during the Vietnam War. It is a working relationship, and there can also be a command relationship. It isn't a big deal amongst professionals. Whomever is appointed as the commander of an organization, is the commander. It is quite possible that a Coast Guardsman could be detailed as the commander, and if that is the case, then they are the Commander (read that as "the Boss!").

Coast Guard does have a law enforcement mission. Some Navy ships will have Coast Guard law enforcement detachments, particularly within US Southern Command's area of operations, so that US Navy ships can interdict maritime traffic transporting possible contraband of drugs, people, or other illicit materials. Members of the Coast Guard law enforcement detachment may make the actual arrests.

The "Coasties" sometimes get a bad rap. However, a lot of them were lost in WWII because they piloted so many landing craft at Normandy and throughout the Pacific.

I stayed in the Navy Reserve after active duty. Our reserve center was manned by Navy, Marines, and Coast Guardsmen. When we'd have common duty weekends, I noticed that most of the Coasties' "right arm rates", such as boatswain's mates, Quartermasters, etc., all wore Vietnam service ribbons. They all served as part of the Viet Nam coastal defense forces and worked with the Navy's Riverine forces. And several of them had Purple Hearts to show for their efforts.

Even though they hold military rank and fall under the UCMJ, they are considered Law enforcement an as such they have the ability to make arrests on the seas after intercepting drug runners or in the 20's and 30's rum runners. The Navy does not have the authority to that, they can detain a vessel until the coast guard arrives.

By Federalized I meant the the Coast Guard is subordinated to the US Navy by an act of congress during an armed conflict. The last time this was done was during the Viet Nam conflict. Every one calls Viet Nam a war but it was not, in order for it to be a war Congress has to declare that we are at war and the last time that happened was the war on terror after 9/11

The missions of the Coast Guard and Navy are different; The Coast Guards mission is to perform search and rescue and Law enforcement duties on the water ways of the US and off the coast of the US and its territory's. When they become subordinate to the Navy they then become pure military.

The mission of the US Navy is pure defense of the shores of the US and to provide a show of force to other countries.

Okay some of you out there will get their knickers in a bunch with what I am about to say.

There are only three true branches of the military. Why do I say this, If you look at the emblem of the Marine Corps that sits behind the Commandant of my beloved Corps, it says United States Marine Corps Department of the Navy. The Marine corps does not require the approval of congress to go to a conflict, they can go on the president say so that is why they have been called the presidents own. The Coast Guard (Coasties) are part of the DOT or what ever they are called now days and can be Federalized for Armed conflict by congress.

So in reality there is only three true military branches as authorized by congress. I know this is splitting hairs but everyone should be aware of the true military hierarchy