It's nice to know that even Richard Nixon and Henry Kissingers, otherwise fairly amoral practitioners of realpolitik, were queasy about the thought of all-out nuclear war.

An excerpt from the NYT story:

The recently declassified papers, from the first days of the Nixon presidency in 1969 until the end of 1974, show that Nixon wanted an alternative to the option of full-scale nuclear war - a plan for a gentler war, one that could ultimately vanquish the Soviet Union while avoiding the worst-case situation.

The papers provided a glimpse behind the scenes at efforts to find choices other than "the horror option," as the national security adviser, Henry A. Kissinger, called the worst-case scripts for all-out nuclear war that were then in place.

Qualms about causing so much death were hardly the only motivation. American officials worried that their nuclear threat lacked credibility because it was so awful that adversaries questioned whether the United States would ever use it.

In a 1969 diary entry, Nixon's chief of staff, H. R. Haldeman, recalled the president's taking part in an exercise that day aboard the Boeing 707 outfitted to conduct nuclear warfare from the air.

"It was pretty scary," Mr. Haldeman wrote. The president asked many questions about "kill results," he wrote, adding about his boss: "Obviously worries about the lightly tossed-about millions of deaths."

The picture was pieced together by William Burr, a researcher at the National Security Archive at George Washington University, from papers released by the National Archives as well as documents obtained under the Freedom of Information Act.

The documents reveal Mr. Kissinger's chilling insight that government budget-crunchers would prefer complete nuclear warfare because it was already planned for and would be cheaper than recasting American capabilities to permit limited strikes.

"They believe in assured destruction because it guarantees the smallest expenditure," he said in August 1973 at a National Security Council meeting in the White House Situation Room. "To have the only option that of killing 80 million people is the height of immorality."

The papers show Mr. Kissinger struggling with a reluctant military and intelligence apparatus to sell them on the idea of limited nuclear strikes. Many doubted that the Soviet Union would settle for a tidy little nuclear war. They feared that a conflagration would quickly follow, devouring cities and killing millions.

But until Nixon took up the matter, the only options in the nuclear playbook involved the highest stakes possible and unspeakable death, and that apparently unsettled him even as he engaged North Vietnam in a war that was claiming civilian casualties.