It was a major, who in 1923, gave a talk to a small group here in Washington, D.C., an Army major, who said that America has the habit of doing and undoing its military. Undoing particularly after every major conflict. At that time, in 1923, Major George C. Marshall spoke of the Army being 125,000, and he said they would have gone down to 95,000 had Congress not gone out of session.

In 1998, Congressman Ike Skelton (D–MO) related this story of George C. Marshall, who as a major in the U.S. Army early in his career warned against dramatic personnel reductions in the aftermath of World War I.

U.S. leadership failed to heed Marshall’s warning in the lead-up to World War II, and the military had to scramble to revitalize its ranks. This trend has continued over the ensuing 89 years. Former Secretary of Defense Robert Gates soberly commented on the pattern:

When it comes to predicting…our next military engagements, since Vietnam, our record has been perfect. We have never once gotten it right, from the Mayaguez to Grenada, Panama, Somalia, the Balkans, Haiti, Kuwait, Iraq, and more—we had no idea a year before any of these missions that we would be so engaged.

When America entered World War II, the U.S. Army consisted of just 180,000 troops, barely above the level Marshall argued was unacceptably low. By the end of the war, he had expanded the force end strength to over 12 million.

While the U.S. will presumably not have to increase its manpower so dramatically any time soon, there is a very real possibility that budget reductions will force dangerous cuts to the Army and Marine Corps. In September 2011, the House Armed Services Committee issued a report detailing what effect sequestration would have on the military, including cutting 143,000 Army soldiers and 57,000 Marines. The report notes that these reductions put the forces below pre-9/11 levels, which “were insufficient to respond to current contingencies.”

Defense has already accounted for half of deficit reduction despite representing only a fifth of the overall budget. The purpose of the military is to protect American interests, not act as a slush fund for the Administration’s fiscal initiatives.

In between the World Wars, the U.S. was drawing out of a major military engagement while simultaneously suffering an economic downturn. Then, just as today, many argued that robust defense capabilities had become less important and that federal dollars should shift more to domestic ends. However, the advances of Nazi Germany in Europe and the bombing of Pearl Harbor proceeded anyway.

While President Obama may have begun the withdrawal from Afghanistan and ordered the strike on Osama bin Laden, myriad threats remain throughout the world, both known and unknown. Rather than using defense as a budgetary tool, the Administration and Congress should heed General Marshall’s warnings and sustain the military during peacetime. This will both deter adversaries and enable America to adequately defend its interests when engagement is necessary.