In his military classic titled ''On War,'' Prussian strategist Karl von Clausewitz uses the word friction to describe the elements of battle that separate the theoretical from the real.
''Everything is very simple in war, but the simplest thing is difficult,'' he wrote. ''These difficulties accumulate and produce a friction which no man can imagine exactly who has not seen war.''
Von Clausewitz included bad weather, fear, confusion, equipment breaking down , plans fouling up.
If anything seemed to characterize the USS Liberty episode, it was this friction generated by the heat of conflict. The men on the Liberty certainly experienced this. So did many of us aboard the USS Saratoga, one of the two US aircraft carriers in the Mediterranean when the Liberty was attacked.
I was a young naval aviator at the time, flying A-4 Skyhawks with the ''Black Diamonds'' of Attack Squadron 216. I was a relatively lowly spear-carrier in a drama whose principal players were admirals, diplomats, and heads of state. But the dominant feeling for an agonizingly long time after the attack began was one of confusion.
Aircraft were hurriedly armed with bombs, rockets, and air-to-air missiles. Flight-deck crewmen in brightly colored jerseys scrambled as the Saratoga turned into the wind, the catapults prepared for launch. The first flight of Skyhawks and F-4 Phantoms hurled off the ship, rendezvoused, and headed for the Liberty.
Those of us assigned to the second launch began our briefing with reports from meteorologists and air intelligence officers. There seemed to be more questions than answers. Who was attacking the Liberty and why - had to go unanswered at this point.
Briefers used large maps of Egypt, pointing out surface-to-air missile sites, antiaircraft emplacements, port facilities, and other military locations. It was well known that the Soviet Union was providing Egypt with military advisers and massive amounts of hardware, including advanced MIG fighters.
The battle in the Mideast was between Israel and its Arab opponents, but this seemed to increase the likelihood of a superpower confrontation - especially if the Liberty had come under Arab attack and the Soviet Union was at least indirectly involved.
Within a couple of hours, however, the confusion was reduced considerably. Israel said it had mistakenly attacked the US ship. The first flight of aircraft from the Saratoga was recalled without engaging in combat, and my flight did not launch. My combat initiation would have to wait for Vietnam.
It's not for me to say how badly the Navy's communications system operated that day, or whether there was a subsequent ''cover-up,'' as some Liberty survivors allege. But I did learn quickly and clearly how right von Clausewitz was about ''friction.''