by the U.S. military to be a European rank. Dwight Eisenhower resigned his Army commission on 31 May 1952, to run for president. After he served two terms, his successor, John F. Kennedy, signed on 23 March 1961, which returned Eisenhower to Active Duty of Regular Army, to the grade of General of the Army grandfathered to December 1944. This rank is today commemorated on the signs denoting Interstate Highways as part of the Eisenhower Interstate System, which display five silver stars on a light blue background. Modern use Summary Official abbreviations below are used in the U.S. Army only. The U.S. Air Force does not abbreviate general officer ranks in signature blocks, but "Brigadier General," "Major General," and "Lieutenant General" (without abbreviating periods) are commonly used. Elaboration After the close of the Second World War, Generals were normally promoted permanently to Brigadier General and Major General, with temporary promotions to Lieutenant General and General to fill senior positions as needed. In theory, a General would be expected to vacate their three- or four-star rank at the termination of their assignment, unless they were placed in an equal or higher-ranking billet. Douglas MacArthur, who served as four-star general and Army Chief of Staff, reverted to two stars after his CoS tour ended but chose to stay on active duty in the United States Army. The practice of using Lieutenant General and General as a temporary rank continues to the current day, although the term "temporary" is in name only since most three- and four-star generals are expected to retain their rank regardless of their assignment. Such officers are also almost always granted permanent retirement rank, as well, in the last grade they held. There have been no officers appointed to the rank of General of the Army since Omar Bradley and, in the 21st century U.S. military, further appointments are highly unlikely unless the United States were to become involved in a major war on the scale of World War II. In the 1990s, the Defense Department gave some indication that the Chairman of the Joint Chiefs of Staff would possibly one day be a position worthy of the rank General of the Army, Fleet Admiral, or General of the Air Force as appropriate. This would be problematic in that with the appointment of United States Marine Corps generals as chairman, there is no current five-star USMC rank. Congressional sources