Sixty years ago this month, near the height of the Cold War, Col. Harry W. Shoup, the new chief of the combat operations center of the Continental Air Defense Command, or CONAD, unwittingly started a Christmas tradition that continues to this day.

The photogenic 38-year-old had already been trotted out for major news media to help give the U.S. defense establishment a more human face. As commander of Truax Field in Madison, Wisconsin, Shoup had done interviews with Time magazine and with Edward R. Murrow on his CBS program “See It Now,” describing his success in building warmer relations with the local community.

Operating from a barracks-style headquarters at Ent Air Force Base in Colorado Springs, CONAD was established in 1954 by President Dwight D. Eisenhower, and its mission was grim. Combining assets from the Air Force, Army and Navy, it was intended to give the Strategic Air Command of Gen. Curtis E. LeMay early warning of a surprise attack on the United States — most urgently, from nuclear-armed Soviet bombers roaring over the North Pole and approaching from Canada. After such an alert, the president would have to decide whether to launch a deadly counterattack against the Soviet Union, resulting in a nuclear war that could kill tens of millions of people. Eisenhower called this the “awful arithmetic” of atomic destruction.

Shoup operated from inside a well-guarded, windowless, three-story blockhouse. In 1954, Elie Abel of The New York Times called this building “the command post for the Battle of North America.” Dominating its multitiered amphitheater, protected by concealed submachine guns, was an upright, 22-by-30-foot sheet of plexiglass, etched with a map of North America and the polar regions, adjoined by flashing red, green and yellow lights.

It was usually Women in the Air Force, or WAFs, as they were then known, who stood behind the transparent map, plotting unidentified objects in the skies, writing in grease pencil. They wrote backward so their markings could be understood by their superiors, sitting in armchairs in front. A suspicious sighting would cause bells to sound.

Next to the chair reserved for CONAD’s chief, Gen. Earle E. Partridge, was a “warning red” telephone, to be used if an attack was imminent. According to a contemporaneous account, if Partridge had to reach for that red phone, it could signal “the time when your whole life will be changed — if you remain among the living a few hours later.” Shoup assured a reporter that “should an enemy attack, the noise of our jets would be the sweetest music an American could hear.”

Three weeks before Christmas 1955, Partridge gave the order for CONAD to be tested with a nine-hour war exercise called Operation Crackerjack, starting with a simulated alert that brought interceptors scrambling into the night.

As Shoup later recalled, one evening that month, with Christmas near, the red telephone sounded. It would not have been irrational for him to suspect — for a moment — that the Russians might actually be on the attack, or at least testing American military preparedness. During the days before Christmas, might not the vaunted U.S. military establishment seem to Soviet strategists temptingly relaxed and vulnerable?

But when Shoup picked up his red receiver, he realized that this call did not augur a nuclear Armageddon. Instead it was a child asking to speak to Santa Claus. Incensed, Shoup at first thought someone was using his ultraclassified warning circuit to play a tasteless prank.

He asked the child, intensely, “Would you repeat that?” and then heard crying, after which an apologetic mother took the phone to explain that they had reached the colonel by dialing ME 2-6681. This number had been printed in a newspaper ad by a local Sears Roebuck store. “Hey, Kiddies!” it said, combining a picture of Santa with an invitation to “call me on my private phone and I will talk to you personally any time day or night.”

The good-hearted Shoup had three daughters and an infant son. As he later told the tale, he quickly realized that the newspaper’s misprint meant that CONAD would soon be deluged by many other such calls. According to the current official website of CONAD’s successor, the North American Aerospace Defense Command, or NORAD, the colonel ordered CONAD’s telephone operators to share Santa’s location with “every child who phoned in that night.”

Had the director Frank Capra made a film about a communications line intended for nuclear war being remade into a children’s conduit to Santa Claus, moviegoers might have thought the story contrived — especially since the colonel who happened to get the accidental call was such a media pro. But when he recalled the episode in later years, Shoup (who died in 2009) always asserted that the episode was not a planned publicity stunt.

For Pentagon publicists, nevertheless, his story was manna from heaven. With their aid, The Associated Press reported on Christmas Eve that CONAD had “begun plotting Santa’s journey” and would “guard Santa and his sleigh on his trip to and from the United States.” According to The AP, Santa had been found to be “traveling about 45 knots at an altitude of 35,000 feet” and was scheduled to reach the United States that evening. (The NORAD website claims that Shoup got his call on Christmas Eve, which is unlikely, since the AP article had already appeared that morning.)

Shoup’s experience was not the last time an American official had to deal with inquiries about Santa. In 1961, for instance, President John F. Kennedy reassured a Michigan girl, Michelle Rochon, who had sent him an anxious letter about Soviet nuclear testing that might jeopardize the North Pole and its most famous inhabitant. J.F.K. told her: “You must not worry about Santa Claus. I talked with him yesterday, and he is fine. He will be making his rounds again this Christmas.”

But it was CONAD’s first, hasty effort to trace Santa Claus’ journey to the United States that ultimately evolved into a much followed annual ritual, now centered on the video-heavy website noradsanta.org, with outside sponsorship by Sears (appropriately), Hewlett-Packard, Microsoft, Verizon and other companies. The program is managed by NORAD’s public affairs office, with more than a thousand volunteers (including Michelle Obama in recent years) handling calls and emails from curious children.

Last week NORAD’s current commander, Adm. Bill Gortney, was quoted in The Gazette of Colorado Springs as saying — with pardonable exaggeration — that tracking Santa was the one annual mission his command could not fail.