It started with a secret. Most people think of the Vietnam War as a conflict contained within the borders of Vietnam, but the reality was much messier and, frankly, much more devastating for the neighbors. If you’ve ever wondered why did the US bomb Cambodia, you have to look past the official press releases of the late 1960s.
The simple answer? Logistics. The complicated answer involves a mix of Cold War paranoia, a desperate attempt to win a losing war, and a massive failure of international law.
Richard Nixon and Henry Kissinger didn't just decide to rain fire on a neutral country because they felt like it. They were trying to cut off the "veins" of the North Vietnamese Army. But in doing so, they triggered a series of events that would eventually lead to the rise of the Khmer Rouge. It’s a heavy topic. It’s dark. But understanding the "why" is the only way to make sense of the modern map of Southeast Asia.
The Ho Chi Minh Trail: A Highway Through Neutral Ground
To understand why the bombing started, you have to understand the Ho Chi Minh Trail. This wasn't a single road. It was a spiderweb of paths, bridges, and underground bunkers that snaked through the jungles of Laos and Cambodia.
North Vietnamese troops used this network to move supplies and soldiers into South Vietnam. They knew the US was hesitant to cross the border into a neutral country. Cambodia, under Prince Norodom Sihanouk, was technically staying out of the fight. But Sihanouk was playing a dangerous double game. He let the North Vietnamese set up "Sanctuary Areas" along the border because he didn't have the military power to stop them, and he hoped that by looking the other way, he’d keep the war from swallowing his people.
He was wrong.
By 1969, the US military was frustrated. They were losing men in South Vietnam to "phantom" enemies who would strike and then vanish back into the Cambodian woods. General Westmoreland and later General Abrams kept pushing for permission to hit those base camps. They argued that you couldn't win the war if the enemy had a safe place to sleep and reload just five miles away.
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Operation Menu: Breakfast, Lunch, and Dinner
When Nixon took office, he wanted a "knockout blow." He authorized Operation Menu. This is where the story gets really weird and secretive. The missions were named after meals: Breakfast, Lunch, Dinner, Snack, Supper, and Dessert.
Between March 1969 and May 1970, B-52 bombers flew thousands of sorties over Cambodia. But if you looked at the official Pentagon records at the time, those planes were supposedly bombing targets in South Vietnam. They faked the maps. They faked the reports. Even the pilots sometimes didn't know exactly where they were dropping their payloads.
Why the secrecy? Because bombing a neutral country is a massive violation of international law. Nixon knew that if the public found out he was expanding the war into Cambodia after promising to end it, the protests at home would turn into a riot.
He was right about that, too. When the "secret" eventually leaked to the New York Times via reporter William Beecher, it set off a firestorm that led to the first wiretaps of the Nixon administration—the very beginning of the trail that led to Watergate.
The 1970 Invasion and the Escalation
The secret bombing wasn't enough. In April 1970, Nixon went on national television to announce a "limited" incursion into Cambodia. He told the American public that US and South Vietnamese troops were crossing the border to destroy the "Central Office for South Vietnam" (COSVN), which was basically the mythical headquarters of the communist insurgency.
They never found a "Pentagon in the jungle." It didn't exist.
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What they did find were caches of rice, some weapons, and a lot of empty huts. The North Vietnamese just retreated further into the Cambodian interior. This move had a catastrophic side effect: it pushed the war deeper into the country. Instead of just hitting the border regions, the US started supporting the new pro-American leader, Lon Nol, who had ousted Sihanouk in a coup.
Now, the US wasn't just hitting supply lines. They were flying "tactical air support" for a failing Cambodian government. This led to Operation Freedom Deal, a much more intense and widespread bombing campaign that lasted until August 1973.
The Human Cost and the Rise of the Khmer Rouge
Here is where the history gets truly tragic. Historians like Ben Kiernan and Taylor Owen have used GPS mapping and declassified data to show that the US dropped more bombs on Cambodia than the Allies dropped in all of World War II.
We’re talking about 2.7 million tons of ordnance.
The bombing didn't just kill North Vietnamese soldiers. It wiped out villages. It killed tens of thousands of Cambodian peasants. If you’re a farmer and your family is killed by planes from a country you’ve never heard of, and then a group of radical insurgents (the Khmer Rouge) shows up and says, "Join us and fight the imperialists," you’re going to listen.
The US bombing acted as a massive recruitment tool for Pol Pot. It destabilized the countryside, drove refugees into the cities, and broke the traditional social fabric of the nation. Without the chaos caused by the 1969-1973 bombing campaign, it is highly unlikely the Khmer Rouge would have ever gained enough support to take over the country in 1975.
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Misconceptions: Was it Just About the Cold War?
A lot of people think the US bombed Cambodia just to "stop communism." That’s a bit of an oversimplification.
By 1971, the US was actually trying to leave Vietnam. The policy was "Vietnamization"—training the South Vietnamese to fight for themselves so the Americans could go home. The bombing of Cambodia was seen by Kissinger as a way to buy time. If they could disrupt the North Vietnamese supply lines enough, it would give the South Vietnamese government a "decent interval" to survive on their own.
It was a cynical strategy. They weren't trying to "save" Cambodia; they were using Cambodia as a buffer to protect the American exit strategy from Vietnam.
The Unexploded Ordnance (UXO) Crisis Today
The war ended decades ago, but for Cambodians, the bombing never really stopped. Millions of "submunitions"—tiny bomblets from cluster bombs—failed to explode on impact. They’re still in the ground.
Farmers today still lose limbs or lives when their plows hit a "yellow lemon" left over from 1970. Organizations like the HALO Trust and MAG (Mines Advisory Group) are still working to clear these fields. It’s a slow, dangerous process that costs millions of dollars. When we ask why did the US bomb Cambodia, we also have to deal with the fact that the consequences are still active in 2026.
Summary of Key Factors
- Supply Lines: The primary goal was destroying the Ho Chi Minh Trail.
- Sanctuary Areas: North Vietnamese troops used neutral Cambodia to rest and refit.
- Political Survival: Nixon wanted to show strength to force North Vietnam to the negotiating table.
- Secrecy: The initial "Menu" bombings were hidden from Congress and the public to avoid international backlash.
- Destabilization: The bombing helped destroy the existing government and paved the way for the Khmer Rouge.
What You Can Do to Learn More
If this history interests you, don't just take a summary at face value. The nuances are in the primary sources.
- Read the Declassified Tapes: Look up the transcripts of Nixon and Kissinger’s phone calls from 1969 and 1970. The callousness with which they discuss "anything that flies on anything that moves" is eye-opening.
- Explore Mapping Projects: Check out the Yale University Cambodian Genocide Program. They have incredible interactive maps that overlay bombing data with village locations.
- Support UXO Clearance: If you want to help with the lingering effects, look into the HALO Trust. They are the boots-on-the-ground experts clearing unexploded bombs from Cambodian farmland so kids can walk to school safely.
- Visit the Sites: If you ever travel to Cambodia, go beyond Angkor Wat. Visit the Tuol Sleng Genocide Museum in Phnom Penh. It provides the brutal context of what happened after the US bombing stopped and the Khmer Rouge took over.
Understanding this period requires acknowledging that military "necessity" often has a very long, very painful tail. The bombing of Cambodia wasn't just a footnote in the Vietnam War; for the people living there, it was the beginning of a nightmare that lasted for generations.