Six weeks before the Japanese bombed Pearl Harbor, President Franklin D. Roosevelt sent a not-so-subtle message indicating the United States was ramping up for war.

On November 1, 1941 – 79 years ago today – he signed Executive Order 8929, which put the U.S. Coast Guard under the Navy’s control, a moved usually restricted to wartime.

The Coast Guard has served in every U.S.-involved conflict since 1798.

Treasury Secretary Alexander Hamilton established the Revenue Marine Service on August 4, 1790. In 1915, it merged with the U.S. Lifesaving Service to create the Coast Guard. It remained under control of the Department of Treasury until 1967, when it became part of the Department of Transportation, and then transferred to the newly created Department of Homeland Security in March 2003.

However, the president can put the Coast Guard’s ships and personnel under Navy control whenever he deems necessary.

That happened on April 6, 1917, the same day the U.S. Congress declared war on Germany and officially entered World War I. Over the next 19 months, the Coast Guard and its Lighthouse Service lost nearly 200 men and five ships, two of which were torpedoed by German submarine. One cutter, the Tampa, took a German sub’s torpedo on September 26, 1918, killing all 131 on board including four U.S. Navy personnel, 16 members of the British Royal Navy, and 111 members of the Coast Guard. It marked the greatest loss of American naval personnel during the war.

After World War I ended with the armistice on November 11, 1918, the Coast Guard returned to the Treasury Department on August 28, 1919.

Just over four months later, the Coast Guard found itself engaged in a different type of war. It busted “rum runners” and other alcohol smugglers after the Volstead Act ushered in Prohibition on January 16, 1920, until Congress repealed it in 1933.

After World War II began in September 1939, the U.S. provided planes, ships, and supplies to England through the “Lend-Lease” program, but stayed officially out of the war for more than two years.

“Officially,” yes. In reality? No.

On September 12, 1941 – two months before FDR placed it under Navy control – the Coast Guard cutter Northland, assigned to Greenland under a defense agreement, found the SS Buskoe moored in a fjord. They determined the ship – purportedly a Norwegian seal-hunting vessel, was instead relaying information to the Nazis using an onshore radio station. Guardsmen seized the equipment and arrested those from the ship and the radio station, meaning the Coast Guard conducted the first U.S. raid of World War II.

Frequent attacks on U.S. ships by the Germans in the Atlantic prompted FDR’s November 1, 1941, executive order to place the Coast Guard under the Navy. It became just a matter of time before the U.S. entered the war. Japan’s attack on December 7, 1941, made that happen.

The Coast Guard performed important amphibious duties throughout the war, with over 350 naval ships – 76 of them LST (landing ship, tank) – 21 cargo and attack cargo ships, 75 frigates, and 31 transports, according to the National Parks Service. The Coast Guard also managed over 800 cutters, 300 ships for the Army, and thousands of amphibious-type assault craft.On December 28, 1945, President Truman signed Executive Order 9666, returning the Coast Guard to Treasury Department control three days later, and it has not been under the Navy’s control since then.