NEWPORT, R.I. » No armchair general here: Bing West has climbed mountains in Afghanistan with American combat troops, watched rocket-propelled grenades streak over his head and come close to dying of cholera. At a lean and flinty 70, he can dodge bullets along with the 20-year-olds he accompanies on infantry foot patrols, although he admits he does it by leaving the body armor behind — an eye-popping risk — and wearing a Boston Red Sox cap instead of a helmet.

He can think of no better life.

"If I wasn’t around, he’d never come home, he’d just stay over there," said his wife, Betsy West.

"Well, I’d come home occasionally," West replied.

West was in fact home on Rhode Island Sound the other day, in between trips to Afghanistan, to talk about his book "The Wrong War," which has landed at just the wrong time for the White House and Pentagon. In the book, subtitled "Grit, Strategy and the Way Out of Afghanistan," West passionately defends the military, but argues that the United States is burning billions of dollars trying to nation-build in Central Asia.

He flatly says that the counterinsurgency strategy behind the war — trying to win over the Afghans by protecting them from the Taliban and building roads, schools and civil institutions — is a failure.

"The question isn’t what the Marines or the Army do, the question is, why are they doing it, and what’s the end state?" West said. "My objection is, they’ve stayed to become the government."

The revolts in the Middle East have far overshadowed anything happening in Kabul this spring, but there are still 100,000 U.S. forces in Afghanistan, and the White House is wrestling with how many to withdraw for an initial pullout in July.

West is yet another headache in the West Wing, although the Obama administration is doing its best to ignore him. The White House had no comment on "The Wrong War," nor did the military’s joint staff.

The Pentagon press secretary, Geoff Morrell, would say only that the book, which ends with last fall’s events, "does not reflect the current state of play in Afghanistan."

West, whose book has received stellar reviews, would be easier to dismiss were it not for his pedigree: assistant secretary of defense in the Reagan administration, Marine infantry officer in Vietnam and author of "The Village," a war classic for 40 years on the Marine Corps’ reading list, about 15 Americans — seven died — who trained Vietnamese farmers to defend their hamlets against the Vietcong.

West has written three recent books on Iraq, the result of 20 months embedded with U.S. troops. He began reporting in Afghanistan in 2008 and is now following a Marine platoon in Sangin, in Helmand province, one of the bloodiest spots of the war.

In West’s view, counterinsurgency strategy in Afghanistan is a feel-good, liberal theology that is turning the U.S. military into the Peace Corps and undermining its "core competency" — violence.

He accuses Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, of "political drivel" for repeatedly saying that the military cannot kill its way to victory. Instead West evokes a view similar to that of Vice President Joe Biden and argues that the United States should reduce its footprint to 50,000 troops, focus on obliterating the Taliban, send small numbers of American advisers into combat with the Afghans, and stop throwing money at a feckless, corrupt government.

His argument is greeted with exasperation by Gen. David H. Petraeus and other top American commanders in Afghanistan, where U.S. troops have aggressively stepped up night raids to capture or kill insurgents, particularly since the fall. In their view, West’s book does not take into account the combination of combat and reconstruction that commanders say has led to progress in Helmand and parts of Kandahar provinces.

American troops "have repeatedly demonstrated that they know how to fight," said Rear Adm. Hal Pittman, a senior spokesman for the American and NATO command in Afghanistan. "They have also demonstrated that they know to rebuild in the wake of the fighting."

One big question about West is why, seven decades in, he is still wading through canals with the Marines and being evacuated by helicopter when he comes down with cholera (Nuristan province in Afghanistan, July 2009). The answer is not readily apparent from his Newport surroundings. After years spent as a professor and dean at the Naval War College, West lives in an airy, compact house across the street from Rhode Island Sound, not far from the Gilded Age mansions of Vanderbilts and Astors.

But as he tells it, he was born into the Marines. During World War II, when West’s father was a general practitioner — he later was an eye surgeon and on the faculty of Harvard Medical School — West’s two uncles were given the third floor of the family house in the Dorchester section of Boston, for use as a clubhouse for their neighborhood baseball team.

"And then the entire baseball team went into the Marine Corps together after Pearl Harbor," West said. When team members came home between deployments (his uncles were in Okinawa and Guadalcanal), they would gather upstairs.

"My mother, being downstairs, thought, ‘Well, the least they could do is baby-sit for Bing,"’ West said. "So for the first five years of my life, I was just sitting around with all these battle-hardened Marines."

"Bing, remember the movies we have of you at 3 years old?" Betsy West interjected. "With your gun and your Marine Corps outfit on, patrolling the porch of your house?"

It took, and it stuck, and today, from a spare home office with sparkling views of the water, West can be found inches from his computer screen, poring over huge files of video he has recorded of firefights in Afghanistan. The other day he played one of a rocket-propelled grenade heading his way in Helmand province. "That was an RPG incoming, here comes another one," he can be heard saying in the video, in between cracks of rifle fire. And then, impressed: "Woo hoo! Right over my head!"

Maj. Jason C. Brezler, who as a Marine civil affairs officer took West around the town of Now Zad in Helmand last year (and who appears in his book), recalls his enthusiasm. "He seems happy just being around Marines, and particularly Marines who are actively fighting," Brezler said. Also, "he has the energy of a 30-year-old."

West, who runs daily to keep in shape, has produced yet another Marine — Owen, his son, who served two tours in Iraq while on leave from his job as a commodities trader at Goldman Sachs.

Today, West said he felt at home on the battlefield and readily accepted the risks, including not wearing body armor, a habit he developed in Vietnam. "They had some flak jackets," he recalled, "but no one wore them because they couldn’t stop a bullet." Today’s hard plates, worn inside vests, can stop bullets, but in West’s view they cut down on mobility.

"I know an awful lot of old fighters from Vietnam are very jealous that I can still do this," he said. "I’m serious."