By all reports, when President Obama's budget is released today, it will envision spending more money on defense. The figure thrown around most is an 8 percent increase over last year. But that doesn't necessarily mean more money to support our men and women in uniform -- and there's good reason to fear otherwise.

The problem is, we won't know the truth until the administration reveals its plans for "supplemental" funding.

When something happens "out of cycle," like a war - which is not in any department's budget -- Congress pays for it by approving supplemental spending. It's been doing just that ever since 9/11.

It made sense. Especially in the early going, it was hard to predict year-to-year what might be needed for operations in Afghanistan -- and Iraq only added to the problem.

So, for the last eight years, you had to add the regular and supplemental defense appropriations together to figure out total Pentagon spending

After a while, however, supplemental spending just became a "Christmas tree" for busting the budget. Plus, we can predict now pretty much what is needed each year for fighting the War on Terror overseas. So it would make a lot of sense now to kill the defense supplemental and give the Pentagon one budget -- ending the Washington shell game of doling out dollars right and left.

But, if the White House kills the supplemental outright, that means it will actually be spending about $70 billion less for defense next year.

A big defense cut is a big problem. Unlike previous wars, the US military never mobilized for this one. During the Cold War, the Navy had 567 ships; today it has 283. The Air Force has about half as many wings. On 9/11, the Army had 10 divisions -- down from 18.

The terror war started with a smaller peacetime force and it was fought on a peacetime budget, so there is no "peace dividend" to be had.

Anyway, a "peace dividend" presumes a peace - and, while Iraq may be calming down, the president intends to boost our commitment in Afghanistan.

Adding to the problem is that defense was underfunded before 9/11. Indeed, the Pentagon's been on a two-decade post-Cold War "buying holiday" -- buying far less new equipment than was the norm up through 1989.

Now the military equipment we do have is getting pretty worn out - the average Air Force bomber is 32 years old. And trucks and helicopters are wearing out five times faster than expected, because the Army has been very busy.

In his speech Tuesday night, the president told the nation: "To relieve the strain on our forces, my budget increases the number of our soldiers and Marines. And to keep our sacred trust with those who serve, we will raise their pay, and give our veterans the expanded health care and benefits that they have earned." Pointedly, he did not promise new and better equipment.

It's great that Obama means to spend more on paying and taking care of our troops -- but that was already the most expensive part of military spending. If he's also shaving billions off the defense budget, he'll be leaving these new members of the armed forces with some pretty shabby stuff.

It gets worse. The president also promised to cut military systems and curtail contracting. It takes about 20 years to procure a new weapons system: If the White House scraps what's in the pipeline now, odds are all those soldiers and Marines recruited in the next few years will be retired before they see their new equipment.

FDR, to whom the president is often compared, faced similar challenges. During his first two terms, he faced mounting fiscal challenges and the constitutional requirement "to provide for the common defense." He cut defense to the bone - until world war loomed.

FDR, however, had a saying. "I never let my right hand know what my left hand is doing." Obama has said he won't do that - that he'll be straight with us. If so, he needs to put all the cards on the table.

When it comes to defense, the test of the president's promise won't be the budget he releases today. We won't know if he plans to shortchange defense until he puts all the numbers for next year's spending plans on the table.

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