Are the navy and marines separate branches of the military if they're both in the the same department?

Answer 1

Yes - though both the Navy and the Marines fall under the Department of the Navy, which is in turn under the Secretary of Defense, they are in fact 2 separate military branches. The Navy is headed by the Chief of Naval Operations, and the Marines by the Commandant of the Marine Corps. Both report directly to the Secretary of the Navy.

Having said that, the Navy and Marines have essentially been linked together since the beginnings of the United States, and though both branches have their own equipment and personnel, Navy and Marines always work closely together for many missions. Marines serve as security forces aboard Navy Carriers and at key Naval bases around the world, and larger Navy ships carry a Marine contingent aboard as part of normal operations.

For example, Navy Corpsman serve as Marine Medics, Navy Seabees attend Marine Corps Infantry school. Marine Corps Aviators fly from Navy ships to support Marine and Navy ground missions, just as well as Naval Aviators support similar missions.

The separation of branches is necessary for a myriad of reasons, but the main ones are training (Marine training is much more small unit discipline oriented, and infantry training is a key element), equipment (Marine missions often require equipment that is specialized to Marine missions), tactics (Marines are ground fighters as well as trained in shipboard defense), and mission (though often operating in concert, each branch is usually tasked with different key elements of a particular mission).

Most Sailors and Marines typically act as though they don't like each other, but he truth is that there is a huge respect for each other among both groups. I have many friends who are former Marines (including a couple of relatives), and while the branch rivalry is there of course, we all realize that neither branch could completely do certain missions without the other. That in the end is why they're 2 branches under one Department in DoD.