Let’s begin with the first question, the answer to which is rooted in demographics and space. The population of Iraq is currently about 32 million. Afghanistan has a population of less than 30 million. The U.S. military, all told, consists of about 1.5 million active-duty personnel (plus 980,000 in the reserves), of whom more than 550,000 belong to the Army and about 200,000 are part of the Marine Corps. Given this, it is important to note that the United States strains to deploy about 200,000 troops at any one time in Iraq and Afghanistan, and that many of these troops are in support rather than combat roles. The same was true in Vietnam, where the United States was challenged to field a maximum of about 550,000 troops (in a country much more populous than Iraq or Afghanistan) despite conscription and a larger standing army. Indeed, the same problem existed in World War II.