Here's the opening paragraph in an article from the Asia Times a few days ago:
The United States Holocaust Memorial Museum in Washington DC plans a new exhibition on Cambodia's Khmer Rouge, but it is uncertain if the American secret bombing of the country, which some analysts say helped the radical Maoists come to power, will be included in the presentation.Some analysts say? I've read quite widely on that period of Cambodian history, and I'm pretty sure I've never come across a writer claiming that the bombing played anything but a helpful role to the Khmer Rouge. Julie Masis, the author of the article, returns to this question near the end and states again that there is some controversy over the bombing and even claims that it may have postponed the eventual victory of the Khmer Rouge. Significantly, no one who espouses this is quoted or even named, though Ben Kiernan, probably the foremost expert on Cambodia in the English speaking world, at least, is mentioned saying that the bombing drove Cambodians into joining the Khmer Rouge. From '65 to '73 there were some 2.7 million tons of bombs dropped over Cambodia by the USA. This is about as much as all the bombs dropped by the Allies during WWII. It's not quite clear whether Cambodia, Laos, or Vietnam can claim to be the single most bombed nation in history. One of them certainly can, and they are all in the top three. Even these days, about once or twice a week, someone in Cambodia is killed by UXO - unexploded ordnance - suddenly and lethally exploding.
So how does a massive bombing campaign help a ragtag bunch of communists sitting in the jungle? The numbers of Khmer Rouge fighters grew under US bombing because it disrupted the lives Cambodian peasants who, unable to carry on as normal, entrusted their children to them. They fed, clothed, housed, and educated these children. They also turned them into an army, the same army that marched into Phnom Penh. Without the US bombing, the Khmer Rouge may well have remained an obscure collection of intellectuals exiled in the jungle.
An exhibition of the period in the Holocaust Memorial Museum, in America for Americans, which makes no mention of the bombing would be a travesty.