English: Diagram of U.S. Military Presidents with highest obtained rank, starting from the first to most recent president to have served. (Presidential images courtesy of educational, governmental and historical public sources. U.S. Air Force graphic/Senior Airman Luis Loza Gutierrez)

GRAND FORKS AIR FORCE BASE, N.D -- The majority of our nation's presidents hold the distinction of once being referred to as brothers-in-arms before they ever held the title of Commander-in-Chief of the U.S. Armed Forces.

In observance of President's Day, we present the following facts: Thirty-one of our 44 American presidents have served in the military, and 12 of them have been general officers (O-7 to O-11 with one, at least in theory, O-12).

The three presidents to hold the highest military ranks were: George Washington, Dwight D. Eisenhower and Ulysses S. Grant, respectively.

Washington held the rank of lieutenant general (O-9) when he died, but in 1976, then-president Gerald R. Ford posthumously appointed him to General of the Armies of the United States.

The only other person to hold the same title was Gen. John J. Pershing, who retired on Sept. 13, 1924.

Although both Washington and Pershing received the same appointment, Washington is considered the higher-ranking officer as President Ford specified he would rank higher than all officers past, present and future. This special appointment would theoretically make Washington a six-star general - or O-12.

President Eisenhower reached the status of a five-star general while serving as Supreme Allied Commander in Europe during World War II (1942-1945). He is one of only nine U.S. officers to have worn the five-star insignia. In all, four Army generals, four Navy admirals, and one Air Force general have officially worn the five-star insignia.

President Grant served as lieutenant general until Congress enacted legislation authorizing the grade of General of the Army on July 25, 1866. Although that title is associated with the five-star insignia, Grant held the position as a four-star general. He saw combat in both the Mexican-American War and the Civil War.

In addition to those who went on to achieve general officer ranks, ten of the presidents obtained the rank of colonel (O-6).

Two of those colonels were also two of our nation's Founding Fathers: Thomas Jefferson (third president) and James Madison (fourth president). Both were militia men. Another president who served as an Army colonel was Theodore Roosevelt (26th president). During the Spanish-American War, Roosevelt helped organized and command the 1st U.S. Volunteer Cavalry Regiment, better known as the Rough Riders. As a former president, Roosevelt volunteered for service in World War I, however, then-president Woodrow Wilson, declined Roosevelt's offer. He was posthumously awarded the Medal of Honor in 2001.

Two of the presidents reached the pay grade of O-5. One of those O-5s was our 36th president and former Navy commander, Lyndon B. Johnson. LBJ served during World War II and was presented a Silver Star medal by Army Gen. Douglas MacArthur for his role on a B-26 bomber mission. The other was President James Monroe (fifth president).

Two other presidents who had notable military service in the Navy were John F. Kennedy and George H. W. Bush, our 35th and 41st presidents respectively. Both men achieved the rank of lieutenant (O-3) and both served during World War II. JFK earned a Purple Heart and a Navy and Marine Corps Medal for heroism.

Our 41st president, President George H. W. Bush, remains the youngest person to ever become an aviator in the U.S. Navy. The former Sailor also earned the Distinguished Flying Cross for his actions during a mission. He completed his attack on Japanese military forces despite his aircraft catching fire and ultimately crashing.

President Bush's son, George W. Bush became our nation's 43rd president, but not before serving as a pilot in the Texas and Alabama Air National Guard. He is currently the only president to have served in the modern-day U.S. Air Force.

However, Ronald Reagan, our 40th president, was part of the Air Force's early history. Reagan served as a captain in the U.S. Army Air Force (also known as Army Air Corps). He helped make more than 400 training films when he was assigned to the 1st Motion Picture Unit in Culver City, Calif. He was discharged from active duty in 1945, prior to the Air Force becoming its own separate military service in 1947.

James Buchanan, our 15th president, held the lowest rank among our military presidents. He was a private (E-1) in the Army, and the only president who enlisted without becoming an officer. He saw combat during the War of 1812.

Buchanan's successor, President Abraham Lincoln, was a private in the Illinois State Militia. He fought in the Black Hawk War, and although his military service was only three months, he was elected to the rank of captain by his militia company. According to Renee Hylton, a historian for the National Guard Bureau, election of officers within militia units was a common practice at the times.