Medium tank other types of tank during normal operations Medium tank Medium tank is a classification of tanks, particularly prevalent during World War II which represented a compromise between the mobility oriented light tanks and the armour and armament oriented heavy tanks. The most widely produced, cost effective and successful tanks of World War II (the Soviet T-34, the American Sherman tank, the Japanese Type 97 and the German Panzer IV) were all medium tank designs, and the success of the concept would later lead to the development of later generations of medium tanks such as the Chieftain. Many of the medium
Opposition to the war in Afghanistan (2001–2014) entering an eleventh year on October 7, 2011 and marking for the U.S. the longest period of sustained warfare in its history – greater than the time the United States was involved in World War I, World War II and the Korean War combined.<ref name="War and Sacrifice in the Post-9/11 Era"></ref> The war in Afghanistan surpassed the length of official U.S. participation in the Vietnam War, 8 years and 5 months, in the spring of 2010 to become the longest-running U.S. war ever. According to a study by the RAND Corporation, an American think tank working for the U.S. military,