"In years gone by, we had all the time in the world but no money. Now we have all the money in the world but no time." -- Gen. Henry H. "Hap" Arnold, 1940

Between the two world wars, America's Army manned sleepy outposts around the world with few troops, outdated equipment, and uncertain missions.

Then a colonel at the service's Infantry School, George C. Marshall recognized these problems, but was in no position to fix them. He could, however, make the Army think about them.

Marshall ordered up a treatise that "checks the ideas acquired from peacetime instruction against the experience of battle." The result was "Infantry in Battle," a collection of 27 combat vignettes, each one highlighting one aspect of combat that made the experience unpredictable, chaotic and disconcerting.

Marshall wanted nascent leaders to think deeply about the challenges of future war. They did. Marshall's men led U.S. troops to victory from the beaches of Normandy to the jungles of New Guinea.

Today's military faces an ambiguous future, much as it did in the 1930s, and again in the Clinton era. A new book, "Kevlar Legions, the Transformation of the U.S. Army, 1989-2005," by John Sloan Brown, documents the challenges of the latter era, as the Army tried to move from a Cold War force to a military instrument for the 21st century.

Even as President Clinton increased the tempo of military operations with deployments to Bosnia-Herzegovina and Kosovo, he underfunded training, readiness and acquisition. He declared a post-Cold War "peace dividend" to balance the budget and pacify a Congress demanding fiscal responsibility.

Like Marshall's men, the 1990s Army couldn't control Washington's follies -- but they could think. Brown's book details how Army brass tried to transform an Army with more time than money.

And they did pretty well. As ill-prepared as the Army was for the challenges of fighting in Iraq and Afghanistan, it could have been worse. Far worse.

The Clinton era innovators copied a key Marshall idea: using field tests and experimental forces to test new concepts, tactics and capabilities. The Army tested extensively in "digitization," exploring the concepts that ultimately would make computers ubiquitous on the battlefield. As Brown observes, there is no substitute for testing men and equipment "in the dirt."

Today's Army can anticipate being ordered to trim its ranks by more than 50,000. That will create tremendous pressure to eliminate "lesser priority" units to save as much combat force as possible.

It would be grave mistake if the commitment to maintain a dedicated experimental force fell victim to that pressure.

Another important initiative of the '90s Army was a commitment to the practice of "future forecasting" -- wargames, simulations and studies that examine alternative future environments and the requirements and capabilities needed to respond to them.

Budget cutters are prone to just pick a future that demands an army that can do only the things they are willing to fund. The problem with the future, of course, is that the enemy gets a vote on what it will be.

And the enemy typically votes to exploit the vulnerabilities imposed on the military by short-sighted budgeters. Future forecasting is an intellectual hedge against self-imposed ignorance about how the future might unfold.

In the 1990s, the Army organized a number of future forecasting activities, like the Army After Next Project. Now, as then, fiscal pressure is demanding the attention of senior Army leaders.

If the generals don't dedicate at least a portion of their time to future forecasting, they will be less prepared for the time when they finally get their money -- but have no time.

James Jay Carafano is a senior research fellow for national security at the Heritage Foundation.