>>> The Marines are no different than any other military service when it comes to their relationship to the CIC. There is no special relationship. <<<
As outlined in 10 U.S.C. § 5063 and as originally introduced under the National Security Act of 1947, three primary areas of responsibility for the Marine Corps are:
1) Seizure or defense of advanced naval bases and other land operations to support naval campaigns;
2) Development of tactics, technique, and equipment used by amphibious landing forces in coordination with the Army and Air Force; and
3) Such other duties as the President or Department of Defense may direct.
This last clause derives from similar language in the Congressional acts “For the Better Organization of the Marine Corps” of 1834, and “Establishing and Organizing a Marine Corps” of 1798. In 1951, the House of Representatives’ Armed Services Committee called the clause “one of the most important statutory and traditional functions of the Marine Corps.”
ref: https://en.wikipedia.org/wiki/United_States_Marine_Corps
That applies to the Navy, Army, and Air Force as well. The USMC. The U.S. Marine Corps is one of the four armed service branches in the U.S. Department of Defense (DoD) and one of the seven uniformed services of the United States. The Marine Corps has been a component of the U.S. Department of the Navy since 30 June 1834.
The USMC is not the President's personal military force. It is part of DOD.
Correct. I was just going to post that.
Here is a link that also states this:
https://www.mca-marines.org/gazette/marine-corps-and-national-security-act
In addition, the Marine Corps shall provide detachments and organizations for service on armed vessels of the Navy, shall provide security detachments for the protection of naval properly at naval stations and bases, and shall perform such other duties as the President may direct: Provided, that such additional duties shall not detract from or interfere with the operations for which the Marine Corps is primarily organized.
Before the War Powers Resolution of 1973 (50 U.S.C. 15411548), only the Marine Corps could be deployed without Congressional authorization and approval. But today, all services can, within the restrictions of the Resolution.
However, that law in no way negates the language of the National Security Act of 1947.
Kabar is correct that the Commander in Chief is the CIC for all services. However, that language in the NSA does not apply to any other service. It has been rarely, if ever, used for anything domestically related, but I am not 100% sure of that.
Why is the language in the law important? Well, if we imagine something big happening, it could be very important.