President Johnson faced a fiendish tangle of problems: He had to restrain Seoul and Pyongyang from locking horns in a war that could quickly engulf thousands of American troops in South Korea, dissuade President Park from withdrawing crack South Korean troops fighting in Vietnam to reinforce his vulnerable home front, and get the captive Pueblo sailors back before the Communists executed them.

He began by rattling his saber as loudly as possible, both to intimidate the North and reassure the South. He rushed the aircraft carrier Enterprise and 25 other warships into the Sea of Japan, within easy range of North Korea, and 360 combat aircraft to bases in and near South Korea.

The Pentagon prepared plans to hit the North with nuclear weapons if it invaded the South. Under one scheme, eerily code-named Operation Freedom Drop, B-52s would incinerate Communist troops and armor with atomic bombs. Another plan envisioned destruction of the entire North Korean air force — nearly 500 aircraft — with round-the-clock airstrikes.

But Johnson chose not to bloody his saber, and thereby exposed himself to charges of weakness. (An outraged New Jersey man sent him a one-word telegram — “Coward” — and a Milwaukee newspaper sarcastically suggested that America’s national symbol be changed from an eagle to a chicken.)

The president believed the wiser course was a diplomatic one. His United Nations ambassador called for debate on the Pueblo in the Security Council, creating a rationale for delaying military action. To hold the South Korean president in check, Johnson gave him a cornucopia of military equipment, including two Navy destroyers.

In February, United States and North Korean negotiators began meeting secretly at Panmunjom in the Demilitarized Zone. The talks dragged on for months as the North Koreans insisted on an American apology for the Pueblo’s “espionage” in their territorial waters. (Washington said the ship was on a legitimate military mission in international waters.) The Americans offered various alternatives short of a formal apology, but the Communists stuck to their demand.