In the United States Army, U.S. Marine Corps, and U.S. Air Force, a first lieutenant is a junior commissioned officer. It is just above the rank of second lieutenant and just below the rank of captain. It is equivalent to the rank of lieutenant (junior grade) in the other uniformed services. Promotion to first lieutenant is governed by Department of Defense policies derived from the Defense Officer Personnel Management Act of 1980. DOPMA guidelines suggest all "fully qualified" officers should be promoted to first lieutenant. A second lieutenant (grade O-1) is usually promoted to first lieutenant (grade O-2) after 18 months in the Army or 24 months in the Marine Corps and Air Force. The difference between the two ranks is slight, primarily being experienced and having higher pay. It is not uncommon to see officers moved to positions requiring more experience after promotion to first lieutenant.
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