refers to the campaign as "the Mexican Expedition". The official beginning and ending dates are March 14, 1916, and February 7, 1917. National Guard units from Texas, Arizona, and New Mexico had been called into service on May 8, 1916. With congressional approval of the National Defense Act of 1916 on June 3, 1916, National Guard units from the remainder of the states and the District of Columbia were also called for duty on the border. By mid-June President Wilson had called out more than 110,000 National Guard for border service. None of the National Guard troops would cross the border into Mexico but were used instead as a show of force. In July 1916, the entire Arkansas National Guard was mobilized for federal service on the Mexican border. Arkansas units began to assemble immediately at Fort Roots, near Little Rock. Of the 2,078 Guardsmen that answered the call, only 1,208 passed the new physical standards for entry into Federal service. The Arkansas Troops received orders on 29 June to move to Deming New Mexico in order to replace regular troops joining the actual expedition into Mexico and prepare if Mexico reacted to the incursion. The Arkansas troops were not engaged in Mexico and returned to Little Rock in February, mustering out of service February 19–24 at Fort Logan H. Roots. This mobilization of the National Guard along the Mexican border was the training ground for many future leaders of the Arkansas National Guard. Many of the officers who led Arkansas National Guard units in the early years of World War I and World War II began their service on the Mexican border. World War I Status on eve of war When the United States declared war on Germany April 6, 1917, less than two months had passed since the last Arkansas National Guard units completed mustering out from duty on the Mexican border. In March 1917, the Arkansas National Guard had been in danger of having its Federal recognition withdrawn. The problem was scarcity of men Company "E", 1st Arkansas Infantry, Little Rock Company, had only twenty men and should have had thirty-two additional men. The reason for the shortage was the lack of interest of the businessmen of Little Rock. The employers would not let men off for training, thereby discouraging their employees from joining. Mobilization While Congress was debating the declaration of war the 1st Regiment was