Although during World War I the United States employed observers on the battlefields of the Western Front, the information they provided lacked the substance and conclusions required to evolve the tactical doctrine of the American Expeditionary Forces (AEF). In initial engagements, the AEF was largely forced to rely, with predictable negative outcome, upon outdated concepts founded largely upon the prejudices of the Army's leadership. In August of 1914 the United States Army and Marine Corps demonstrated strong foresight, considering the isolationist perspective of the nation, in detailing officers to the battlefields of Europe. These officers were given little guidance, but their mission was clearly to report on military actions and developments in what was becoming the largest struggle in history. A significant military development of World War I noted by the U.S. was the advance of offensive infantry tactics to cope effectively with the characteristics and lethality of the modern battlefield. The United States, with a two and one-half year opportunity to observe tactics prior to the engagement of the AEF, arguably should have benefited from the experience of others. However, this was not the case. The AEF in its initial engagements, performed much as its European counterparts did at the onset of the war. Eventually the AEF performance improved, but only as U.S. soldiers and Marines gained personal battlefield experience.