When last we worked at length on something about former secretary of state Henry Kissinger, he was on his knees in the White House, praying beside Richard Nixon shortly before the latter’s resignation 39 years ago next week.

Now he’s back, a third of the way into our colleague Dan Balz’s excellent new book, “Collision 2012,” where he’s leaning on New Jersey Gov. Chris Christie to run for president back in the summer of 2011.

Christie demurred.

“You can do this,” Kissinger said.

“I haven’t given any deep thought to foreign policy,” Christie protested.

“Don’t worry about that,” Kissinger assured. “We can work with you on that.” “Foreign policy is instinct, it’s character,” he explained, “that’s what foreign policy is.” (Well, it also helps if you can find Iraq on a map.)

Billionaire financier Ken Langone asked Christie to a breakfast at the Rocker Club in Manhattan. Christie expected a small group. Sixty people showed, not including John Mack (former Morgan Stanley CEO), David Koch and others on speakerphone.

If Christie ran, Langone said, “everyone in this room has committed [to] raise every dollar you need. . . to have a successful campaign. You won’t have to worry about raising money.”(That sure would make things easier.) Kissinger was there to speak for everyone and to urge Christie to run.

President Bush II later called. Barbara Bush called Christie’s wife. In the end, of course, Christie said no.

The behind-the-scenes reporting throughout — heck, the Christie chapter alone — makes the book a must-read. Balz takes us quickly through the memorable GOP primaries with Rick “Oops” Perry and the improbables, until Romney, battered, hurting for cash and thoroughly boxed in on immigration, finally emerges.

“He came out of the primaries with liabilities and did nothing of note to erase them during the heat of the summer,” Balz writes.

Throughout that summer, the fearsome Obama juggernaut, with many months, even years, to marshal its forces, blasted away with negative — not to mention distorted — ads seeking to portray Romney as an out-of-touch, heartless plutocrat.

The infamous “47 percent” secret video, released in September, obviously didn’t help — something Romney alluded to in a post-election interview with Balz when he talked about “a lousy September” vs. “a great October,” when he clobbered Obama in the first debate, unified and energized his base and held his own in the next two debates.

Obama, who appeared to have suffered a stroke during the first debate — actually a common first-debate malady for incumbent presidents, with the exception of Bill Clinton — was able to recover some in the next two debates.

In the interview, Romney cited the late drop in unemployment below 8 percent — which changed the critical “wrong track/right track” perception for voters — and Hurricane Sandy as key factors for his loss.

Asked about immigration, Romney said he had decided “I’m not going to make this a campaign about immigration.”

The problem, as Balz analyzes, is that Latinos may have thought differently. “Obama won Florida by a point,” he writes, “by winning the Hispanic vote, including the Cuban American vote.” In Colorado, Obama’s margin among Latinos “leaped” from 23 points in 2008 to 52 points last year, “a reminder of the crippling Republican deficit among the nation’s fastest-growing minority group.”

In the end, “the election turned out almost precisely the way the team in Chicago had predicted,” Balz reports, and the way most polls predicted, with Obama winning 51-47.

“Campaign 2012 settled little,” he concludes. “Billions were spent to produce a status quo outcome in the balance of power in Washington.”

But it was a fascinating ride, which Balz captures vividly in this most worthy sequel to “The Battle for America 2008,” written with the late Haynes Johnson.