Silver Spring, Md.

ROBERT GATES, the secretary of defense, has proposed a budget overhaul that will go a long way toward improving our national security, but more can be done to meet his long-term goal: creating the right military for the 21st century.

Not since Henry Stimson’s tenure from 1940 to ’45 has a defense secretary been faced to the same degree with simultaneously fighting a war and carrying out far-reaching reforms. Yet there are three major changes Mr. Gates should add to his agenda, and they deserve President Obama’s support.

First, the Air Force should be eliminated, and its personnel and equipment integrated into the Army, Navy and Marine Corps. Second, the archaic “up or out” military promotion system should be scrapped in favor of a plan that treats service members as real assets. Third, the United States needs a national service program for all young men and women, without any deferments, to increase the quality and size of the pool from which troops are drawn.

At the moment, the Army, Navy and Marine Corps are at war, but the Air Force is not. This is not the fault of the Air Force: it is simply not structured to be in the fights in Iraq and Afghanistan. While Army, Marine and Navy personnel have borne the brunt of deployments, commonly serving multiple tours, the Air Force’s operational tempo remains comparatively comfortable. In 2007, only about 5 percent of the troops in Iraq were airmen.