Why is the Army chief of staff asking Congress for an extra $25 billion for next year? Because equipment wears out a lot faster in wartime - but Congress typically won't fund the replacement costs in time of peace.

It's not that the Bush administration has underfunded the military. Anything but. Defense spending is at a post-Cold War high, totaling almost 4 percent of everything the country makes and spends (otherwise known as the gross domestic product, or GDP). The Army alone got $98 billion this year. And the Army has enough money, troops and equipment to fight in Iraq and Afghanistan and help defend Korea, as well as do numerous other jobs the world over.

But it can't do that forever without wearing out the force - and the force is wearing out. Rebuilding it will cost money - a lot.

This should surprise no one. When you drive your car all the time, you spend more on gas, oil and repairs. And your car wears out faster. That's why high-mileage used cars sell for a lot less.

Our army is the same way. Operations in Iraq are wearing out trucks three to five times faster than normal. Helicopters are being used at five times their normal rate. Stockpiles of ammunition that sat around during the Cold War have been used up.

The strain is greatest for the National Guard, citizen soldiers that respond to such domestic crises as floods, fires and earthquakes, here at home as well as in combat missions overseas. The Guard continually has to borrow troops and equipment from one unit to fill out another so as to be ready to fight in Iraq and Afghanistan.

By July 2005, according to one report by the Government Accountability Office, 100,000 pieces of equipment had to be moved around to make sure the troops had everything they needed. As a result today, on average most Guard units are missing about a quarter of their materiel. Much of it winds up left over in Iraq to be used by follow-on units or given to the Iraqis. By last count, this amounted to more than 64,000 pieces of equipment, including trucks, radios and other gear.

All this has be replaced or fixed, or the military won't be ready for the next war. That will cost tens of billions of dollars and will takes years after the war in Iraq is over.

Ghosts of Vietnam

The problem is that the Army knows that when wars end, military spending typically goes way down, not up. That results in a "hollow force," a term coined by Gen. Edward "Shy" Meyer after Vietnam. The Army then looked fine on paper, but it didn't have nearly enough money to rebuild after the war. Meyer commanded more than a dozen divisions. He told the president that about two of them were ready to go to war.

This was the Army I was commissioned into as a second lieutenant from West Point. I called it the "OK" Army. We didn't have enough money to train, but that was OK, because we didn't have enough troops to train with, but that was OK, because we didn't have enough equipment for the troops we didn't have. It was all OK - as long as we didn't have to fight anybody. America's Army stayed broke for almost a decade until the Reagan defense buildup of the 1980s.

I know another officer who was in the OK Army. His name is Pete Schoomaker. He is now the Army chief of staff and at the White House lobbying for more money - because he desperately doesn't want to see another Hollow Army on his watch.

The 800-lb. Gorilla

The Army is lobbying hard to start fixing itself now because it knows that the long-term projections for defense spending are bad. Even if the level of military spending remains the same after Iraq, over the next decade it will continue to shrink as a percentage of GDP to something like 3 percent or less. And the military's "real buying" power will shrink along with it.

People in the Pentagon know that budgets likely will continue to drop regardless of who's in the White House after 2008 because budget projections show that "mandatory" spending, the things the government has to fund every year regardless of what the president and Congress want, are going to skyrocket.

Most of that rapid increase in spending will be because of such entitlement programs as Medicare, Medicaid and Social Security. America is getting older, and health care is getting a lot more expensive. Unless something is done soon, the result will be a perfect storm that consumes the federal budget, leaving little money left over for nice-to-have things - like defending the nation.

Zero Confidence

The military has zero confidence that the politicians on the other side of the Potomac are going to seriously address this issue anytime soon. They figure that as soon as Iraq cools down, the big checks won't be so big anymore. So they are trying to get what they can now to get the Army into as good a shape as possible to weather the lean years ahead.

That's why Schoomaker is going to the White House, military hat in hand.

James Carafano is Senior Research Fellow for National Security and Homeland Security at The Heritage Foundation and author of the new book "G.I. Ingenuity."