Former defense secretary Donald H. Rumsfeld (Jacquelyn Martin/AP)

We weren’t going to read former secretary of defense Don Rumsfeld’s book, “Rumsfeld’s Rules,” a collection of aphorisms and anodyne nostrums he’s collected and espoused over the years.

But book jacket praise by Dick Cheney and Henry Kissinger convinced us to take a look. And anyone who quotes Chicago Mayor Rahm Emanuel and Seneca, Machiavelli and Jon Stewart is on to something.

Rumsfeld offers us nearly 400 “rules,” on business, war and politics, including: “Lawyers are like beavers. They get in the middle of the stream and dam it up.” Or this: “When you’re up to your ears in alligators, it is difficult to remember that the reason you’re there is to drain the swamp.”

It’s a brisk and fun read.

On the other hand, his detached analysis of the fiasco known as the Iraq War can be a little unnerving.

Rumsfeld occasionally lapses into a variant of his “stuff happens” insouciance when reporters quizzed him about the looting and chaos that gripped Iraq after the invasion.” (The same “stuff” happened in the 1989 invasion of Panama, we recall, so it was wholly predictable and probably preventable.)

“Many mention the failure to find WMD in Iraq as if intelligence failures of that magnitude had never happened before,” Rumsfeld writes.

Of Afghanistan: “ . . . I recall no intent — expressed publicly or privately — to engage in a large, open-ended occupation,” nor a National Security Council consideration or decision to do that. It all happened “gradually,” he writes. So the “rule” here is?

Rumsfeld quotes Emanuel’s saying that “you never want a serious crisis to go to waste” and then cites approvingly how Lyndon Johnson used the alleged crisis after the Gulf of Tonkin incident in 1964 to get support for the Vietnam War. (And that worked out well.)

Sept. 11, 2001, he told Politico last week, was a “terrible, terrible thing for the country. But people immediately assumed that that would be the end” of reform at the Pentagon. In fact, he writes in his book, 9/11 also “provided an impetus to achieve many of the changes that were needed to meet the threats of the 21st Century.” So there you go.

He says he’s “happy as a clam these days.”