Once upon a time, there was a president who promised to spend less on defense and give us more. And he did -- in a manner of speaking.

The president was Jimmy Carter. America's tragedy in Vietnam had ended. The military was worn out after almost a decade of war. Congress had "financed" combat operations largely by deferring the purchase of new weapons, deferring maintenance, and otherwise cutting corners -- paring bases in NATO countries, reducing troops on Korea's DMZ, etc.

But when Carter came to the White Houses in 1977, rather than simply invest in rebuilding America's military, he promised America one better. He endorsed defense Secretary Harold Brown's "offset" strategy.

Instead of fixing the equipment on hand or buying new stuff, the Pentagon would invest in "next generation" Technology that would offset the fact that the Soviets had a lot more ships, planes, and people. Brown planned to provide the American military with an overwhelming technological competitive advantage.

Offset also allowed Carter, in the face of a poor economy, to cut defense spending to the bone. By "skipping a generation" of weapons, the White House could gut the equipment purchasing budget and throw a few extra dollars into researching new weapons -- and claim it was not being weak on national security.

To its credit, research started in the Carter years did produce some new capabilities -- most of it, however, did not get to the field until the Cold War was almost over.

In the meantime, America did get more for less -- just as the president promised. But, the "more" was just a lot more risk. No matter what fancy strategy or cost-savings a president promises, under-funding the military hollows out the force, leaving it with not enough to maintain trained and ready troops, pay for current operations, and prepare for the future. That's what happened under Carter. All this became all too clear when the Army Chief of Staff General "Shy" Meyer testified before Congress that he had 16 divisions on paper -- only four of them were ready go to combat.

President Obama won't unveil his first defense budget for a few weeks, yet. But all signs indicate that the "offset" is back.

In his address to Congress, the President promised to eliminate unnecessary "Cold War" weapons -- and get the troops the equipment they really need. That sounds like Carter all over again.

All the "Cold War" weapons still in the Pentagon's inventory -- tanks, planes, ships -- are already bought and paid for. And they are still in use -- from aircraft carriers to cruise missiles. Scrap them, and you'll have to replace them.

Every system that we are buying now or plan to buy has been justified over the last 20 years by Democratic and Republican presidents and funded by Democratic and Republican Congresses based on "future requirements" not refighting the last war.

Missile defense is a case in point. We didn't start building defenses until after the Cold War ended, and we built it not to counter the Soviet threat but deal with new missile powers like North Korea and Iran.

If the president chooses to scrap all or any of this, there will be little or nothing to replace it. It takes years to get a new program up and running. Many troops entering the military now will be retired before they see any of the future equipment this administration proposes.

It gets worse. Obama also says he also wants fewer contractors. That means the military will have more difficulty getting capabilities "off the shelf" to meet immediate needs.

Washington is swirling with rumors that the services are being forced to put their capabilities on the chopping block to dampen defense spending. By one account, the Navy may have to cut an aircraft carrier and an air wing -- that's about 80 aircraft.

The military is already starting to have a hollow ring to it, and we haven't even seen the White House's first budget.

While the overall Pentagon budget might wind up looking slightly higher than last year's, take a close look at the part "buying stuff." Acquisitions will likely take a big whack -- a down payment on the offset that will leave our troops without the tools they need.

James Jay Carafano is a senior fellow at The Heritage Foundation and the author of GI Ingenuity: Improvisation, Technology and Winning World War II.