Three percentage points in six weeks. That's the trickle of good news from the Pentagon, which seems at last to have its full attention on protecting our troops from roadside bombs.

On Tuesday, military officials told members of the House Armed Services Committee that about 75 percent of the U.S. Humvees in Iraq were either fully armored or, in most cases, retrofitted with armored plates. On Oct. 4, the figure had been 72 percent.

Faring much worse, with just 10 percent armored, are the five- and seven-ton vehicles that transport troops and often draw escort duty for supply convoys.

It has been clear for some time that our nation went to war in Iraq with too few troops, although President Bush and his secretary of defense, Donald Rumsfeld, won't admit as much. Less apparent, but equally important, is the magnitude of the Pentagon's failure to properly equip the Marines and soldiers that we sent to fight and die in this awful cauldron.

A recent Associated Press photo showed Camp Pendleton-based Marines stacking sandbags onto a plywood ceiling to protect their Humvee as they prepared for battle near Fallujah. While the picture affirmed the innovative spirit of our troops, we wondered why, 20 months after the invasion of Iraq, some of our friends and neighbors were driving into battle without full armor plating that has proved to save lives.

Iraqi insurgents have exploited this weakness. Nearly every day for months, U.S. men and women have died after roadside bombs exploded near their vehicles. Most vulnerable have been unarmored Humvees and the lightly protected transport trucks.

It turns out that these vehicles can be upgraded with 3/8-inch-thick, hardened steel plates that dramatically improve survival rates. Tragically, the Pentagon has moved slowly to get the armor into the hands of troops.

Generals in Iraq want all the vehicles upgraded. Last week, officials told Congress they expect 100 percent protection by February or March.

At first glance, this performance looks terrible. Commanders began requesting armor in June 2003. Pentagon planners didn't place major orders until November or December. Manufacturers reached full production in February 2004, according to testimony before the congressional committee in April.

Now the Pentagon says it is in high gear. But the slow-motion performance exhibited by the military-industrial system may point to deep-seated problems that threaten national security.

We don't know whether commanders moved quickly to recognize that roadside bombs would become a major threat. Cumbersome military procurement regulations probably bear much of the blame. A new law to streamline the system, authored by Armed Services Committee Chairman Rep. Duncan Hunter, R-Alpine, was signed by Bush early this month.

Pentagon bloat could be responsible -- congressional aides point out that equipment acquisition bureaucrats outnumber the entire Marine Corps.

What seems certain is that although U.S. factories were able to absorb increased orders for armor -- once they were finally placed -- years of industrial contraction has left our nation with diminished capacity to ramp up for a major war.

During the presidential campaign, Sen. John Kerry tried and failed to make political hay from outdated reports of shortages of body armor, radios and other equipment. The military had already fixed those issues.

Upgraded armor is much more important, and our failure is much more deadly.