In 1964, Keith Connolly was a young Air Force pilot and was among the first Americans to fly sorties in the F-100 Super Sabre fighter bomber targeting the North Vietnamese communist insurgency.

“The atmosphere was that we were going over there to provide the firepower necessary to bring the North Vietnamese to their knees,” said Connolly, who now lives in Arizona after retiring from 35 years in the Air Force.

The average American back then paid scant attention to the long-simmering civil war on the Indochina peninsula, where the U.S. had sent military advisors but was not yet involved in direct ground combat.

“It was the only war in town, and it was going to be over with tomorrow,” Connelly recalled. “Boy, were we wrong.”

On March 2, 1965, the U.S. commenced such bombing raids in earnest with Operation Rolling Thunder, a massive, joint Navy-Air Force campaign of more than 300,000 attack sorties over 3½ years.

Connolly and hundreds of other Air Force and Navy pilots would be drawn into that bombing campaign focused on North Vietnam, an operation now largely regarded as a failure that escalated U.S. involvement in the civil war, pulled American ground troops into combat and led to scores of downed U.S. flyers spending years in North Vietnam POW camps.

“What it led to was an escalation of military force on the American side and a corresponding effort to keep up on the Vietnamese side, which lasted for another 10 years,” said Marilyn B. Young, a history professor at New York University who co-edited the book “Iraq and the Lessons of Vietnam, Or, How Not to Learn from the Past.” “I think Rolling Thunder was a profound failure.”

“It was just a mess, from start to finish,” said James H. Willbanks, a veteran of the war and author of numerous books on the subject, including “Abandoning Vietnam: How America Left and South Vietnam Lost its War.”

Scholars point to numerous reasons Rolling Thunder was ineffective: heavy-handed restrictions on targets, shifting and vague operational goals, underestimation of the enemy, lack of intensity and confused evaluation.

“And in the process, we lost over 500 aircraft to no particular end,” Willbanks said.

No magic formula

Rolling Thunder sprang from a cantankerous debate and mutual mistrust between President Lyndon Johnson’s civilian security advisers, particularly Defense Secretary Robert McNamara, and top military officials over how to deal militarily with the spread of communist insurgency in Southeast Asia.

Johnson’s advisers argued for waging of a limited war, a concept that was largely anathema to military heads who had cut their teeth on the full-scale World War II.

Such a limited bombing campaign would employ gradual pressure on North Vietnam “until they finally reached the point where the North Vietnamese leadership would say, ‘We give. We say uncle,’ ” said Edward Marolda, a naval historian and author of “By Sea, Air and Land: An Illustrated History of the U.S. Navy and the War in Southeast Asia.”

“If you’re not achieving success when you start bombing, then you would increase the bombing and military pressure,” Marolda said. But there was always a self-imposed “ceiling” on that pressure because Johnson and McNamara feared that bombing too intensely — or too close to the border of China — could trigger direct Chinese or Soviet Union intervention on behalf of North Vietnam, he said.

“They did not want to generate World War III,” he said, but the U.S. never found that “magic formula” of pressure.

“As it turned out, gradual escalation gave the enemy time to improve anti-aircraft defenses and to take other measures to reduce the impact of the bombing,” said Mark Moyar, author of “Triumph Forsaken: The Vietnam War, 1954-1965.”

When North Vietnam did not cave in, Rolling Thunder morphed into “Plan B,” with a goal of stemming the flow of supplies and personnel to the insurgency in the South, primarily through the Ho Chi Minh Trail, Marolda said.

Pilots in danger

As Rolling Thunder rumbled on, missions became ever more risky for the men flying them.

Connolly recalled that the anti-aircraft gunners in North Vietnam in 1964 were “not that good.”

“They were like us,” he said. “In fact, in our squadron, we did not have a person who had been involved in combat before. This was all new to us.”

When Connolly went back for his second tour of duty, he found that Rolling Thunder had ushered in a new era.

“When I returned in ’65 and things got more intense and we started losing more air crews, it became very apparent that we had underestimated our foe,” he said.

“In the early days, when you’d go across a target, they’d shoot at you. They weren’t horribly accurate. Later on, they wouldn’t shoot at you until they got the ideal shot. They became much more disciplined.

“Conversely, we got better at our job, which was basically getting into the target, delivering munitions and escaping.”

Some didn’t escape. Among them was Sen. John McCain, then a Navy aviator who was shot down near Hanoi in October 1967 and spent the next six years as a POW.

The pilots Connolly flew with in those days were a small, tightly knit group.

“There were not a lot of fighter pilots, particularly who were flying the F-100 or the F-105,” he said. “We all knew each other because we rotated around that system. So if you didn’t know the guy personally — and many of them you did — you knew someone who did. So each loss was amplified by the fact that, hey, we lost a really good guy here or there or he went in and we never heard from him.

“It’s always tough when you’ve lost three of four people on a given sortie and the next day you have to go up there again.”

Ground war

Rolling Thunder ushered in American ground combat because such a vast operation had to rely on more jets based in South Vietnam, aside from aircraft sortieing from Thailand and carriers at sea.

“So you’re going to have to put airplanes on the ground in Vietnam, and that’s in fact why in March of ’65 we put the Marines ashore in Da Nang, to secure the air base,” Willbanks said. “And of course, once you get the Marines ashore, you can’t secure an air base by sitting in the wire. You’ve got to patrol, and pretty soon what starts as a defensive means looks very much like offensive operations. And fairly quickly we’re in a real, no-kidding shooting war on the ground.”

Johnson tacitly admitted that Rolling Thunder had failed by announcing in March 1968 he would not run for re-election and that the U.S. was going to enter peace negotiations with North Vietnam, Marolda said.

In the decades since Rolling Thunder officially ended in the fall of 1968, the operation has routinely been held up as classic example of the pitfalls of political micromanagement of war.

“There’s some truth to that,” said Christian G. Appy, professor of history at the University of Massachusetts, Amherst and author of “American Reckoning: The Vietnam War and Our National Identity.”

“But what should not be forgotten is that while there were some constraints on bombing in the North, our bombing of the South was utterly unconstrained,” Appy said, adding that 4 million tons of bombs were dropped on the South, compared with 1 million tons in the North.

Appy argues that despite the destruction of Rolling Thunder, it had no impact because there was no military solution to be had in Vietnam.

“So long as the government in South Vietnam didn’t have the sufficient support of its own people, the American objective of creating a permanent, non-communist country called South Vietnam was just not going to happen.”

The legacy

Moyar said Rolling Thunder is an example of America’s recurring tendency to overestimate air power. “The precision of air power has improved greatly since Vietnam, but we continue to see the nation’s enemies adapting in ways that limit the damage that can be inflicted from the air.”

Col. Gregory Daddis, an academy professor of history at West Point, said he advises his students to look to history for perspective rather than specific lessons because context changes over time.

“In the case with Rolling Thunder, I think there’s something to be learned here about an honest dialogue between civilian policymakers and senior military leaders about what military force can achieve,” Daddis said.

A germane question Rolling Thunder raises is what beliefs and assumptions did civilian and military leaders hold that made them believe the U.S. could bend or break the will of Hanoi’s leaders through the military, in particular air power, he said.

“That’s important because it suggests that military power might not always be able to help you achieve your political objectives,” he said.