While Nixon was bugging Kissinger, guess who was bugging Nixon.

On April 27, 1971, the White House operator connected a call from President Richard Nixon to his national security adviser, Henry Kissinger. Kissinger didn't know it at the time, but Nixon had his now-famous Oval Office tape machine running. The two men were exhilarated because there had been a breakthrough, a secret message from the People's Republic of China. Premier Zhou Enlai had sent an invitation, through a Pakistani channel, for a Nixon emissary to come to China and arrange what would become Nixon's historic trip to China, 30 years ago this month.

A recently released transcript (click here to read it) shows that it was a bracingly cold-blooded conversation. The Chinese message had mentioned Kissinger as the possible emissary, and Kissinger did eventually get the assignment. But on this day, Nixon wanted to torture Kissinger with the possibility that he'd name someone else. He mentioned the U.S. representative at the Paris talks on Vietnam, Ambassador David K.E. Bruce, but then asked, "How about Nelson?" meaning Nelson Rockefeller, Kissinger's longtime patron. At first, Kissinger said no ("he wouldn't be disciplined enough"), but when Nixon kept raising other possibilities, Kissinger came back to Rockefeller ("I could keep him under control"). Nixon also suggested Kissinger's military assistant, then-Col. Alexander Haig, because "he's really tough." This carried the wounding implication that Kissinger was not. Kissinger sucked it up, and Nixon tossed him a bone ("Henry, it wouldn't have happened if you hadn't stuck to your guns").

There was a weird little interlude involving former New York Gov. and two-time Republican presidential nominee Thomas E. Dewey, who had passed away earlier that year:

Nixon: If Dewey were alive, he could do it.

Kissinger: Nelson would be better.

Nixon: But Dewey isn't alive.

And there were two cutting little interludes involving George Bush the Elder, then ambassador to the United Nations:

Nixon: How about Bush?

Kissinger: Absolutely not, he is too soft and not sophisticated enough.

Nixon: I thought of that myself.