Photo Courtesy of U.S. Army/Spc. Sean Kimmons

In announcing his plans for making substantial cuts in Pentagon programs and budgets, Defense Secretary Robert Gates argued that his intent was to "balance" the force between the requirements of persistent irregular conflict, as in Iraq and Afghanistan, with the need for high-tech systems.

Unfortunately, balance is not the only, nor even the primary, virtue of military forces. Overall capability and the size of military forces matter even more, as our experience of Iraq should remind us.

Indeed, U.S. forces have adapted remarkably well to their counterinsurgency missions, but they are too few to accomplish the task without excessive strain. Their problem is not a lack of "balance," but a lack of numbers.

To be fair, Gates has been given a thankless task by President Obama. The administration's budget plans--which will see defense spending fall to less than 3% of gross domestic product while domestic entitlements and debt service rise to 16% of GDP--are an inevitable formula for American military decline. Gates has artfully arranged the deck chairs, but the Obama budgets plot a Titanic-like course. We just don't know which iceberg will be fatal.

Nor should we believe that defense "reforms" can bridge the gap between our strategic ends and military means. The fact is that America gets what it pays for--a lot more than we pay for--from our men and women in uniform.

In fact, past defense reforms arguably have increased costs to taxpayers and deprived U.S. forces of timely modernization. It is worth remembering that the current generation of front-line weapons, the aging legacy of the Reagan buildup of the 1980s, originally was ridiculed as gold-plated excess. In war, there is no such thing as excess capability.

The United States faces a critical choice. President Obama wants to help finance his expansive and expensive domestic program by cutting military spending. He seeks another "peace dividend" as in the 1990s — but this is hardly an era of peace. It now falls to the Congress, which has the constitutional obligation to raise, train, equip and fund America's armed forces, to preserve the military power that preserves the peace.

Thomas Donnelly is a resident fellow at AEI.