The official mission of the United States Marine Corps is to serve as an expeditionary force in readiness, as outlined within the National Security Act of 1947, with three primary areas of responsibility: Seize or defend advanced naval bases and other land operations in support of naval campaigns, the development of tactics, techniques, and equipment used for amphibious operations in coordination with the Army and Air Force, and to fulfill such other duties as the President of the United States may direct.
Given the fact that the President of the United States is the Commander in Chief of the Armed Forces of the United States, that last clause (above) may appear to some as a redundant mission, but “…other duties as the President may direct” has been specifically addressed to the Marines since 1798, reaffirmed in 1834 and 1951. The Marine Corps has more often than not performed combat operations of a non-naval nature since Tripoli, the War of 1812, the battle at Chapultepec, numerous campaigns in Central America and the Caribbean, during World War I, and the Korean War. The common thread for each of these is that the President of the United States ordered the Marines to perform them —but of course, this was back when we still had a commander in chief.
The Marines, as with its sister service the U. S. Navy and other branches of the Armed Forces, continually develop, review, exercise, and modify (as necessary) various contingency operations plans at locations throughout the entire world. It is this process of operational planning that enables Marine Corps commands to “execute” combat operations within a short time frame once the national command authority that combat operations are necessary. This is what happened in 1965 —sort of.
In January 1965, Fleet Marine Force headquarters placed the 3rd Marine Division (Okinawa) on alert status. Brigadier General Frederick J. Karch, a veteran of several amphibious operations during World War II, was then serving as the Assistant Division Commander of the 3rd Marine Division, was detailed to form a brigade around the 9th Marine Regiment, designated 9th Marine Amphibious Brigade . In 1965, the 9th MAB consisted of 1st Battalion, 9th Marines and 3rd Battalion, 9th Marines —both of which were at sea with the US Navy’s Task Force 76, then called an amphibious ready group (ARG).
Five months following the Gulf of Tonkin incident, Lyndon Johnson  was still struggling with having to make a decision about the US role in South Vietnam. A flurry of messages between Washington, Hawaii, and Saigon served to confuse the alert status of the Marines. By the end of January, General Westmoreland (Commanding the Military Advisory Command, Vietnam) requested that Admiral Ulysses S. Grant Sharp  (Commander in Chief, Pacific) support him by stationing the US Seventh Fleet off the coast of Vietnam for an extended period. With nearly forty years service in the Navy, Admiral Sharp knew better than most that the only thing gained from keeping Marines penned up aboard ship is that it makes them testy. Accordingly, Admiral Sharp declined Westmoreland’s request, offering instead a 72-hour window.
Meanwhile, General Karch was flying back and forth between Okinawa, the Special Landing Force Camp at Subic Bay, and Saigon attempting to plan training exercises in Thailand, and concurrently, making final plans for possible combat operations in Vietnam.
In early February, Viet Cong forces attacked a US compound at Pleiku in the Central Highlands. They killed nine Americans, wounded 128, and damaged or destroyed 122 aircraft. Higher authority ordered the Marines to station a battery of HAWK missiles at Đà Nẵng as part of a defense shield. The movement of one battery was no easy task; it required 27 aircraft to move personnel and equipment from Okinawa to Đà Nẵng.
Operational reappraisals were occurring almost by the minute in Washington, Hawaii, and Saigon. President Johnson sent a delegation to Vietnam to confer with Westmoreland and Ambassador Maxwell D. Taylor and determine the feasibility of airstrikes against North Vietnam and the likely impact on the communists operating in RVN. It was McGeorge Bundy’s recommendation that Lyndon Johnson develop a “sustained reprisal policy.” And, whereas Westmoreland earlier concluded that the introduction of combat forces would only make matters worse in Vietnam, the Pleiku attack seemed to suggest that the insurgency had taken a new direction.
The internal power struggles continued in South Vietnam; no one was quite sure who was in charge of the government in any given hour of the day. President Johnson decided in mid-February to approve a “limited and measured” air campaign against the North Vietnamese, which the US military would refer to as ROLLING THUNDER. General Westmoreland made up his mind about the number of ground troops needed to defend the air base at Đà Nẵng. He submitted a request to the JCS on 22 February for a 3-battalion Marine brigade. By this time, General Karch and two battalions were afloat off the coast of Vietnam. At the end of the month, President Johnson approved a two-battalion brigade with the mission to protect Đà Nẵng airbase from enemy intrusion.
Brigadier General Karch met with General Westmoreland on 25 February 1965 to discuss the plan for a Marine landing at Đà Nẵng. Two days later, Karch met with the Vietnamese I Corps commander, Major General Nguyễn Chánh Thi (the virtual warlord of South Vietnam’s five northern-most provinces). As Karch and Westmoreland’s operations officer, Brigadier General William E. DuPuy were arriving at Thi’s headquarters, he noticed the presence of a New York Times reporter within the compound. DuPuy told Karch, “This is not a good sign.” Moments later, a phone call from Saigon ordered DuPuy, “Get Karch and his staff out of Vietnam as soon as possible.”
Karch and his staff returned to Subic Bay, and then flew back to Okinawa. I can see everyone in Karch’s party scratching their heads and muttering obscenities. At about the same time as this was taking place, the US Department of State cabled Ambassador Taylor and ordered him to seek RVN’s pre-approval for a Marine landing. For two days, Taylor wrangled with various Vietnamese officials. Some of these had no objection to the employment of Marines at Đà Nẵng, but voicing concern for the reaction of local citizens, the official request was that the Marines come ashore “inconspicuously.”
I served as a Marine for 3 decades; in all that time, I never saw an inconspicuous amphibious landing. The RVN demand caused US officials in Washington to reconsider using the Marines at all. Instead, Assistant Secretary of Defense John McNaughton suggested using the 173rd Airborne Brigade. It could land at Đà Nẵng in the middle of the night and, in the absence of tanks, amphibian tractors, heavy weapons, and a bad case of attitude, no one would even know the brigade had arrived.
To their credit, both Westmoreland and Taylor objected to the employment of a light infantry brigade: the Marines were self-sustaining and had participated in the development of Operation Plan 32 (Vietnam) and a number of related contingencies, since 1959. Admiral Sharp sent a message to the JCS that might have sounded a bit like this: “The Commanding General, 9th MAB is already at Đà Nẵng, for Christ Sake!” By 7 March, the national command authority overruled all previous objections to landing Marines in Vietnam. The way was clear —the war was on.
Should anyone wonder if there is a point to this essay, it is only this: to illustrate why the Vietnam War had such an unhappy ending for the United States. Defensive strategies always do.
 In the Marine Corps, brigades are non-permanent organizations tasked for specific missions. The size of a Marine Brigade may vary from two battalion landing teams to two regiments, with aviation and logistical support units attached. Today, the term “expeditionary” replaces the term “amphibious.”
 During World War II, Lyndon Johnson asked for, and received, a naval reserve commission as a lieutenant commander. Initially relegated to inspecting navy shipyards in Texas and Louisiana, Franklin Roosevelt decided to use Johnson to spy on Douglas MacArthur in the Southwest Pacific. From this sojourn emerged several interesting fairy tales about Johnson having been attacked by the Japanese, but none of these has any greater credibility than the imagined attacks against Hillary Clinton during a taxpayer funded junket to the Middle East. Some claim that Lyndon Johnson was the model for a fictional character Commander Neal Owynn (played by Patrick O’Neal) in the Otto Preminger film In Harms Way.
 Admiral Sharp was highly critical of US policy in the Vietnam War. In 1969 he authored an article titled We could have won in Vietnam Long Ago, and in 1978 he published a book titled Strategy for Defeat: Vietnam in Retrospect.