What price do you put on protecting American troops in combat?

Put another way, has the $45 billion to $50 billion invested in purchasing some 25,000 MRAPs — mine-resistant, ambush-protected troop-carrying vehicles — been worth it?

Former defense secretary Robert M. Gates, in speeches and in his book “Duty ,” pretty well set the public version of the story.

In 2004-05, improvised explosive devices, or IEDs, became the major threat to U.S. forces in Iraq, causing up to 80 percent of fatalities. Adding armor to Humvee troop carriers didn’t solve the problem.

Gates was in Iraq when he read an April 2007 USA Today article about MRAPs, whose V-shaped bottoms provided added protection to their passengers. Upon his return to the Pentagon, he was told that because there was not enough money, only 1,300 MRAPs had been built out of about 6,000 ordered. When he initially pushed for more rapid procurement, “not a single senior [Pentagon] official, civilian or military, supported his proposal for a crash program to buy MRAPs,” said Christopher J. Lamb, former deputy assistant secretary of defense for resources and plans and now at the National Defense University.

Gates decided “to make the MRAPs the Pentagon’s number one acquisition priority for moral reasons,” Lamb told a June 24 House Armed Services Committee hearing. Gates “believed America should do everything possible to protect the volunteers it sends to war,” Lamb said.

Field commanders in Iraq had begun putting in piecemeal requests for MRAPs as early as June 2003, but in Washington “those in charge of Pentagon requirements did not think these options were a good fit for the U.S. military,” Lamb said.

It took almost three years after the first requests from the field before the Pentagon requirements system went to Congress in a supplemental funding request for a major purchase of MRAPs, Lamb said. Pushing it along in 2007 were Democratic Sens. Edward M. Kennedy (Mass.) and Joseph R. Biden Jr. (Del.).

Why the delay? Many Pentagon decision-makers did not like purchasing heavy, armored vehicles that would have limited value in future wars.

There also was the expense.

“MRAPs cost three to seven times as much as an up-armored Humvee, from $600,000 to $1 million per vehicle,” Lamb said.

In the end, more than 10,000 MRAPs were fielded in 18 months. At that point, “only about 5 percent of casualties were attributable to IEDs, even though insurgents were targeting MRAPs with IEDs for symbolic reasons,” Lamb said.

In his book, Gates wrote about visiting Walter Reed Army Medical Center and meeting a soldier who told him, “ ‘Your MRAP saved my life.’ I managed to keep my composure — barely. I didn’t fully appreciate at the time the emotional toll my duties were taking on me.”

About 25,000 MRAPs were built through 2012, including models for mine-clearing, ambulance service and vehicle recovery — some 25 variants overall. One analysis found that “MRAPs cost less than replacing and caring for the casualties from the IEDs . . . and politically the MRAPs helped shore up public support for the war effort,” Lamb said.

Despite MRAPs’ success in Iraq and more recently in Afghanistan, Gates’s procurement decision is still controversial within the military and among outside experts.

Lamb pointed out to the House committee a danger that senior civilian Defense Department officials “frustrated with Pentagon processes are increasingly inclined to jettison disciplined defense analyses in favor of intuitive and impressionistic decision-making, which I think would be a mistake.”

Some military analysts noted that the IED casualty rate was already declining because of changes in Gen. David H. Petraeus’s counterinsurgency tactics, so the MRAPs’ impact was marginal.

Meanwhile, since 2007 the Army and Marines have been focusing on the Joint Light Tactical Vehicle (JLTV) to replace Humvees. The Army is projected to buy about 50,000 from fiscal 2015 to fiscal 2040, while the Marines’ plan calls for purchasing 5,500 JLTVs from fiscal 2015 to fiscal 2021, according to the Pentagon’s December 2012 Selected Acquisition Report.

Together, the Army and Marine Corps have decided to keep only 10,000 MRAPs. The Army plans to keep 8,500 — most mothballed for contingencies — and get rid of about 7,500. Defense News has reported that about 2,000 MRAPs in Afghanistan are up for auction because it costs nearly $300,000 each to return them to the United States. Small numbers are being taken by U.S. police departments, and Pakistan is reportedly seeking some. Many are bound to be scrapped.

One other aspect of the MRAP procurement story is worth recording. While the initial delay can be mainly attributed to the force development and requirements system — which is always concerned with the next big war — you cannot discount what Lamb described as the military “service cultures that generally undervalue irregular warfare capabilities.”

“Service organizational cultures disincline the Pentagon to field capabilities for irregular warfare that compete with established warfighting programs,” Lamb said. To some degree, that led years ago to the Special Operations Command having its own procurement capability for specific gear and services for its unique missions.

Now, according to Lamb, “if we want better niche capabilities for irregular warfare or joint capabilities for other major mission areas” outside traditional ground, sea and air warfare, “we will have to embrace alternative decision-making mechanisms and processes.”

His major message is: “The intense oversight and rigid processes that govern large, long-term major acquisition programs are not appropriate for quick fielding of creative solutions in irregular and rapidly evolving circumstances.”

Lessons from MRAP should be put to use.

For previous Fine Print columns, go to washingtonpost.com/fedpage.