For the fourth time in half a century, the United States finds itself at war. But this time there is no draft, the conflict is being conducted with an all volunteer force. The Department of Defense has 1.37 million active duty troops, 1.28 million reserves (including National Guard) and 670,000 civilian employees. During the peak of the Korean war (1950-53) there were 3.6 million troops on active duty. For the peak of the Vietnam war (1965-72) there were 3.4 million troops on duty. For the Gulf War (1990-91) there were 2.1 million. For the current War on Terrorism there are, so far 1.5 million. The main problem is calling up reserves. This is never popular, at least in the long term. Many reservists are eager to serve, but if the service goes on for six months or more, most reservists feel the financial pinch (a sharp drop in income because their military pay is much less than their civilian income.) The War on Terrorism is, so far, a low intensity operation. But major demands have been made on the navy (to keep many ships at sea in distant locations for long periods) and for air force transport aircraft (which are being run round the clock.) The military is already asking for more people. But recruits are not rushing to join and the only source of the trained people needed are the reserves. Somewhere down the line, there are going to be problems.