May 2, 1907, Lejeune assumed command of the Marine Barracks and Naval Prison, Navy Yard, Cavite, on May 6, 1907. He assumed command of the First Brigade of Marines on June 15, 1908, and was promoted to lieutenant colonel on May 13, 1909. He was detached on June 8, 1909, and ordered to return to the United States. He then attended the U.S. Army War College, graduating in 1910. Lieutenant Colonel Lejeune embarked on board on May 26, 1912, with the Second Regiment, First Provisional Brigade Marines, for Cuba. He disembarked at Guantanamo Bay, Cuba, on June 8, 1912, and was in command of the District of Santiago from June 9 to July 14, 1912. On July 15, 1912, Lejeune embarked on board and sailed for Colón, Panama. July 18–29, 1912, was spent at Camp Elliott, Panama. The Marine Corps Association was founded on April 25, 1911, at Guantanamo Bay by the officers of the 1st Provisional Marine Brigade, under command of Colonel Littleton W. T. Waller. Although the 1st Provisional Marine Brigade disbanded shortly after, the MCA remained active. Two years later, again at Guantanamo Bay, officers of the 2d Provisional Marine Brigade, commanded by Colonel Lincoln Karmany, formally organized the Marine Corps Association. Colonel Karmany appointed then-Lt. Colonel John A. Lejeune as its first head of the executive board. After returning to the United States, Lejeune was again called upon for expeditionary duty. He sailed from Philadelphia, February 20, 1913, as second in command of the First Regiment, Second Provisional Brigade Marines, and disembarked February 27, 1913, at Guantanamo Bay, Cuba. Then-Lt. Colonel Lejeune became the first head of the Marine Corps Association with the goal of professional advancement among Marines. He returned to Philadelphia on board USS Prairie on May 2, 1913. On November 27, 1913, Lejeune sailed from New York with the 2nd Advanced Base Regiment, his ultimate destination Veracruz, Mexico, but returned to the United States to receive his promotion to colonel on February 25, 1914. Col. Lejeune participated in the Tampico Affair. Colonel Lejeune and his unit eventually landed in Mexico on April 22, 1914, and participated in the United States occupation of Veracruz. He returned home in December 1914, this time to report to Marine Corps Headquarters in Washington, D.C., to become the Assistant Commandant of the Marine Corps to Major General George Barnett, Commandant of the Marine Corps. He was promoted to