Elliot Brennan's comparison between the Khmer Rouge and ISIS raises a number of questions.

No one is more aware than I of the terrible cost of Khmer Rouge rule in Cambodia between 1975 and 1979. It was a period that devastated a country I knew well, and which led to the death, as Elliot rightly notes, of at least 1.7 million people, including several of my close friends.

But there are several reasons for offering a more nuanced view of what occurred under the Pol Pot regime than Elliot suggests, and reasons for wondering whether the Cambodian experience has all that much to tell us about what is happening in the Middle East. There are also some factual points that need adjustment.

The fact that the US bombing campaign had a terrible cost is beyond dispute. However, the revelations that bombing began in 1964 under President Johnson, before Nixon's authorisation of Operation Menu, which lasted from 1969 to 1973, needs to be put against the fact that little of this bombing, however damaging it may have been, was in populated areas. During the more than six months I traveled around Cambodia in 1966 (including in the northeast of the country), there was simply no general awareness that bombing was taking place.

There is another problem in relation to the bombing. While it is quite clear that the Khmer Rouge made the bombing a successful basis for propaganda and recruitment, we simply cannot say with any certainty just how much this contributed to its recruitment campaigns. Interviews with former Khmer Rouge cadres can only tell part of the story. For the record, I have acknowledged the importance of the bombing for recruitment in my book Before Kampuchea: Preludes to Tragedy.

More to the point, and on an issue of fact, the overthrow of Prince Sihanouk was not the result of the American bombing campaign, as Elliot suggests. The coup was mounted by men of the Cambodian right who had been Sihanouk's close associates. It is not correct to link the bombing and the March 1970 coup. The best account of the coup is provided by David Chandler in his book The Tragedy of Cambodian Historywhere he describes the anti-Vietnamese feeling and resentment of Sihanouk's consort's family as prime factors in his overthrow.

As to the extent to which the bombing explains later Khmer Rouge actions, I think this is far from clear.

Philip Short's excellent biography of Pol Pot presents a picture of a man and his close associates who were ready to transform Cambodia well before the US bombing took place. As for the phrase 'Year Zero', now so routinely associated with the Khmer Rouge, David Chandler, whose judgment I accept, maintains that this was never used by them. The term was originally associated, it is suggested, with Lenin. But it seems to have gained currency in relation to Cambodia because of its use as a book title by Francois Ponchaud, Cambodge Année Zéro.

What were the Khmer leaders' views of Cambodia's past?

As Elliot notes, Pol Pot referred to Cambodia's Angkorian past as a symbol of what the nation he now ruled over could achieve. So it is not all that surprising that the physical symbols of the past were not destroyed by the Khmer Rouge regime. While looting on a major scale took place in the Angkor region after the Khmer Rouge was defeated in 1979, there is no evidence of the Khmer Rouge setting out to damage the Angkor temples while it was in power. Indeed, the one serious instance of damage at Angkor Wat appears to have been the result of a missile launched by Lon Nol forces.

The priceless treasures in Phnom Penh's National Museum remained untouched while Pol Pot was in power. And despite claims made in some editions of the Lonely Planet Guide to Cambodia that the Silver Pagoda was looted, my own judgment is that the collection of Buddha images that can be seen there today is very much the same as could be seen before 1975. The one notable loss from the royal palace in the 1975-79 period was the royal regalia. The sacred sword, known as the Preah Khan or 'Lightening of Indra', has never been recovered. 

Action against genocidal groups is indeed a necessity. But one cannot readily equate one genocidal group with another. The lack of a religious element in the Cambodian genocide (or 'auto-genocide', to use Jean Lacouture's term) is surely vitally important given the central role religion plays in the beliefs of ISIS.

In short, one genocide may have some similarity with another, but it is just as important to give due weight to the differences between them.

Photo courtesy of Wikipedia Commons.