When he was told that some in the Army were dismissive of press reports on the mistreatment of patients at Walter Reed Army Medical Center, Secretary of Defense Robert Gates, according to one witness, grew “very, very quiet.” Within two weeks, the Walter Reed commander was out of a job.

This kind of decisive silence has been employed by Mr. Gates to good effect in scandals ranging from misdirected nuclear parts to the cremation of both fallen American soldiers and pets at the same facility.

To those who know this Eagle Scout with 28 years of experience in government, Mr. Gates’s subdued efficiency is not surprising. To those of us who haven’t had the pleasure, his transformational ambitions and strategic boldness are surprising indeed.

When Mr. Gates was nominated in late 2006, conservative suspicions and liberal hopes coincided. Mr. Gates, then a member of the Iraq Study Group, was expected to ease the American retreat from Iraq and begin the American engagement with Iran. Foreign-policy realism was back. When asked at his confirmation hearing if America was winning in Iraq, Mr. Gates replied, “No, sir” — a candor that foretold change. But since Mr. Gates was the opposite of an ideologue, it was difficult to predict what form that change might take.

In the 17 months of his tenure, some of this transition has been stylistic. One Pentagon source (who didn’t want to be identified for fear of sounding like a suck-up) calls Mr. Gates “extraordinarily quick and extraordinarily even” and praises his “sense of humor and candor behind closed doors.”

But the most important shift has been substantive. Donald Rumsfeld — along with the early President Bush — set out an ambitious vision of military transformation. The Pentagon would use a period of relative international calm to make bold leaps in military capabilities so America would be unmatched in future wars. That calm ended on September 11, 2001, but the Afghanistan and Iraq wars were still generally seen as temporary distractions from this great transformational purpose.

Far from treating Iraq as a distraction, Mr. Gates has posed the question: Why not concentrate on winning the wars our soldiers are currently fighting? In a series of groundbreaking speeches, Mr. Gates has argued that asymmetrical conflicts in the “long war” against “violent jihadist networks” will remain the likely face of battle for decades to come, that “procurement and training have to focus on that reality,” and that shaping civilian attitudes in these conflicts will be just as important as winning battles.

There have been at least three practical outcomes of the nicely rhymed Gates Doctrine — “the war we are in … is the war we must win” — in Iraq and beyond.

First, Mr. Gates has pushed to deploy technologies immediately useful in low intensity conflict, particularly unmanned aerial vehicles. “Three armed Predators over Sadr City,” my military contact says, “have hammered anyone challenging our forces. They help account for the eagerness for a cease-fire.”

Second, Mr. Gates is institutionalizing the teaching of counterinsurgency strategy. The old theory, says my contact, went: “If we could do the big stuff — major combat operations — we could take care of the little stuff, the asymmetrical stuff. But the little stuff turned out to be more prolonged and difficult.” So the Army’s new manual on “Full Spectrum Operations” trains new officers to conduct simultaneous offensive, defensive, and “stability operations” — things like political reconciliation, providing basic services, promoting local government. “The human terrain,” my source says, “is the decisive terrain, and Gates gets it.”

Third, Mr. Gates argues that while American military power can be a prerequisite for stability, winning asymmetrical wars requires other elements of American power. So he calls for “a dramatic increase in spending on the civilian instruments of national security — diplomacy, strategic communications, foreign assistance, civic action, and economic reconstruction and development.”

The Gates Doctrine has helped right a listing Iraq War — and has met opposition. Getting the Air Force to deploy unmanned vehicles instead of concentrating on expensive, manned aircraft has been, Mr. Gates says, like “pulling teeth.” Elements of the defense establishment, he charges, have been “preoccupied with future capabilities and procurement programs, wedded to lumbering peacetime process and procedures, stuck in bureaucratic low-gear.” Recently — seven years after September 11, five years after the Iraq War began — Mr. Gates noted that portions of the military are still not on a “war footing.”

With Americans engaged in a war, this scandal dwarfs any Mr. Gates has faced. In confronting it, the “realist” has become genuinely transformational.