Nixon's double-speak in his public address regarding of the bombing of Cambodia in 1970 is amazing:
"We stopped the bombing of North Vietnam. We have cut air operations by over 20 per cent. We've announced the withdrawal of over 250, 000 of our men. We've offered to withdraw all of our men if they will withdraw theirs. We've offered to negotiate all issues with only one condition: and that is that the future of South Vietnam be determined, not by North Vietnam, and not by the United States, but by the people of South Vietnam themselves. The answer of the enemy has been intransigence at the conference table, belligerence at Hanoi, massive military aggression in Laos and Cambodia and stepped-up attacks in South Vietnam designed to increase American casualties. This attitude has become intolerable. We will not react to this threat to American lives merely by plaintive, diplomatic protests. If we did, the credibility of the United States would be destroyed in every area of the world where only the power of the United States deters aggression."

So what Nixon is basically saying is that the US had to bomb Cambodia in order to retain the ability to prevent acts of aggression - terrifyingly twisted logic.

"The Long Secret Alliance" by widely respected Cambodia expert John Pilger digs deeper into the US intrigue in Cambodia. You can view the full Pilger article here.

Further reading:
http://www.chron.com/cs/CDA/ssistory.mpl/nation/2594306
Chomsky on Cambodia
http://www.edwebproject.org/sideshow/history/index.html
http://www.robertscheer.com/1_natcolumn/97_columns/070897.htm
http://www.parish-without-borders.net/Cambodia/camb-home.htm
http://www.zmag.org/zmag/articles/hermansept97.htm
http://www.worldsocialism.org/polpot.htm
Media criticism
http://www.globalpolicy.org/security/issues/polpot.htm