Beyond this, several themes seem to emerge, and while Gaddis nowhere makes this explicit they do seem to have some application to whatever-name-you-want-to-ascribe-to-our-current-conflict:
1. Ideas matter: As much as the Cold War can be seen as a triumph of the U.S. over the U.S.S.R., it was market capitalism defeating communism. However a key aspect was a softening of some of capitalisms harder edges, which caused reduced support for collectivism amongst "the proletariat" - Gaddis even alludes to the notion that under a perfectly Hobbesian market, many people are less free, in effect.
And to the extent that poverty and underdevelopment fuel the appeal of radical Islamism, the problem is with us today. As an example, consider Greg Djerejian's (per usual) perceptive commentary on the Israeli-Hezbollah cease fire:
Let’s be clear. Beating Hezbollah ultimately must rely more on what might be described as counter-insurgency tactics, not some Dresden redux. To beat back Hezbollah one must moderate the 40% of Lebanese who are Shi’a, by over time having them pledge their primary allegiance to a strong central government, one that is sharing the economic fruits of Lebanon’s revival with all ethnic groups, so as to ultimately render the social welfare arm of Hezbollah largely irrelevant. (emphasis mine)2. Relatedly Ideals Matter. And living up to them, at home as well as abroad is important. Truman seems to have realised this before everyone else (it's no mistake the Bush frequently adopts Trumanesque rhetoric, btw) - if we want to preach to the rest of the world about freedom and democracy, then we had better be free and democratic ourselves. In Truman's time, this meant integrating the army (above howls of protest) and pushing (with varying degrees of success, it must be said) for civil rights legislation. In counterpoint, there was McCarthyism which, to put it mildly, did not help our image (not to say that there were not Communist spies, of course there were, but the irresponsible demogaguery and fear mongering did not present our political system in the best light.)
3. Transparency Is Increasing. And relatedly, the populous has less tolerance for what was once known as a "credibility gap" - the difference between rhetoric and action. This bit LBJ, and especially Nixon. (Though Gaddis makes the point that lying to the people is somewhat ok if the lie passes a sort of "sunlight test;" the necessity of the secrecy being clear in retrospect - Nixon's early diplomacy with China or Eisenhower denying the U2 program being examples of things which pass this test, whereas LBJ's escalation of Vietnam and Nixon's Watergate and Pentagon Papers actions, not so much.) The problem we are facing today is the words of Truman and the photos of Abu Ghraib.
4. Peoples and Nations Have Interests. For all the talk of the Cold War representing a stable "bi-polar" system, the time was rife with examples of the tail wagging the dog - little countries dragging the superpowers this way and that (what was the strategic importance of Korea, or Hungary, or Vietnam, or Afghanistan if not for "dominos?") Further, there is a danger in having your best laid plans rely on your allies doing what you know to be best for them, even if they themselves disagree (see, e.g., de Gaulle, Charles).
5. Lastly A Time For All Things. Sometimes ugly choices and realpolitik-based compromises are the best you can hope for. Gaddis certainly believes that in the first 20 years or so following WWII bold actions aimed at 'winning' the Cold War in the immediate future were not only futile, but destabilizing in a particularly dangerous manner. He even posits a plausible and very, very frightening counterfactual for the outcome of the Korean War if such an aggressive line had been taken - the 'bold' action would have been trying to decisively win that conflict through the use of tactical nuclear weapons.
But at on the other hand, a lack of ambition tends to ossify that status quo. While Kissingerian detente was stable, it wasn't good. Opinions differ as to whether it was Reagan's boldness or the simple failure of Communism as a viable economic system, but it seems clear that the Soviet Union needed a push (and perhaps a more worldly leader, such as Gorbachev - the only Soviet leader after Lenin to have attended a university). The difficulty lies in deciding whether it is a time for patience or a time for action - neither is always true, nor always false.
Pooh's View: A very crisp, useful and educational overview. Also a very quick read. Highly recomended to people of my generation who don't already know much about the period from 1946-1990.