I recently read his 1994 book Diplomacy and it is an honest and cogent walk through and analysis of various crisis and diplomatic imbroglios that shaped his tenure as a diplomat under both Nixon and Ford. His pithy analysis of the Vietnam conflict should be required reading for every history student.
One of the sections that he wrote on Guerrilla War was brilliant and I thought that I would share it with you as it has some tangency with the problems that beset us today:
In a conventional war, a success rate of 75 percent would guarantee victory. In a guerrilla war, protecting the population only 75 percent of the time ensures defeat. One hundred percent security in 75 percent of the country is far better than 75 percent security in 100 percent of the country. If the defending forces cannot bring about nearly perfect security for the population - at least in the area that they consider essential - the guerrilla is bound to win sooner or later.
The basic equation of guerrilla war is as simple as it is difficult to execute: the guerrilla army wins as long as it keeps from losing; the conventional army is bound to lose unless it wins decisively. Stalemate almost never occurs. Any country engaging itself in guerrilla war must be prepared for a long struggle. The guerrilla army can continue hit and run tactics for a long time even with greatly diminished forces. A clear cut victory is very rare: successful guerrilla wars typically peter out over a long period of time. The most notable examples of victory over guerrilla forces took place in Malaya and Greece, where the defending forces succeeded because the guerrillas were cut off from outside supply sources (in Malaya by geography, In Greece due to Tito's break with Moscow).
Neither the French nor the American army, which followed in its footsteps a decade later, ever solved the riddle of guerrilla war. Both fought the only kind of war they understood and for which they had been trained and equipped-classical conventional warfare based on clearly demarcated front lines. Both armies, relying on superior firepower, strove for a war of attrition. Both saw that strategy turned against them by an enemy who, fighting in his own country, could exhaust them with his patience and generate domestic pressures to end the conflict. Casualties kept mounting while criteria to define progress remained elusive.