Starting six years ago, the U.S. Army was ordered by Congress to increase its strength. As a result, army strength went from 492,000 to 562,400 in a few years. Now, Congress has ordered strength to be cut back to 513,000 over the next four years. The army would have preferred to have not increased its strength in the first place, so that resources could be concentrated on training and equipment for the troops it had. But the politicians get obsessed with the numbers, and the idea that bigger is better. The troops believe that better is better, but that's a hard sell for the politicians. Meanwhile, the marines were also ordered to increase strength a bit, while the navy and air force had substantial layoffs.
Despite the war on terror, and some small increases (and decreases) the U.S. military is still at an all time post World War II low in terms of personnel strength. In 1950, just before the Cold War and Korean War manpower increases, the army had 593,167 troops. In 2000 (before a slight increase for the war on terror) there were 482,170. For the navy, 1950 strength was 380,739 compared to 373,193. Air force strength in 1950 was 411,277, compared to 355,654 in 2000. Only the Marines, thanks to an Act of Congress in the 1950s, have increased their strength from 1950 (from 74,279 to 173,321 in 2000.) But the military, man for man (and woman) is more lethal than its 1950s counterpart. This is a result of new weapons and equipment which, even taking inflation into account, is much more expensive. The defense budget in 2000 was (after accounting for inflation) four times what it was in 1950. Personnel costs are more than tripled (taking inflation into account) since 1950, largely because all troops are, since 1975, volunteers. Moreover, an increasing number of support jobs are being done by civilians. And then there is automation, which has come to the military as it has to most jobs in the civilian sector.