Across America this weekend, there was silent mourning and rage. A nation that should be inured to such horror shuddered in revulsion.

How could it have happened? we all wondered. How, in a land where justice is supposed to prevail, could the San Diego Chargers have failed to cover the point spread against the Seattle Seahawks?

The details of Saturday's game are almost too painful to recount. Favored by 10 1/2 points, the Chargers coasted to a 21-0 advantage and led, 21-7, with five seconds left. Seattle quarterback Jim Zorn dropped back to pass from the Chargers' 39-yard line, scrambled some 20 yards behind the line of scrimmage while the clock ticked down to 0:00, then lofted a long pass on a wing and a prayer.

The Seahawks' Dan Doornink caught it miraculously at the two-yard line, but was tackled there, as people who bet the Chargers minus 10 1/2 points breathed a sigh of relief. They did, that is, until they saw the yellow flag on the field, realized that a game cannot end on a penalty and watched with resignation as San Diego yielded an "irrelevant" touchdown with time expired.

NBC's prognosticator, Pete Axthelm, had touted San Diego on the air, and the next day said, "A lot of people have complained that we are encouraging gambling on this program. But after this game you might suspect that I'm working as a double agent for Gamblers' Anonymous. Anybody who followed my advice on the Chargers may never bet again."

Some of us had previously discovered that betting on football is a form of cruel and unusual punishment. A few weeks ago, I vowed that I was not going to subject myself to such torture any more and (except for one minor lapse when Houston played Pittsburgh in a Thursday night game) I have stayed on the wagon.

Betting football can become such a ritualistic part of life that kicking the habit may be as difficult as abjuring cigarettes, booze or hot fudge sundaes. But my plan for swearing off has proved so effective that Gamblers' Anonymous may invite me to conduct seminars.

Instead of avoiding all temptation, I continue to watch televised games with academic interest. When the point spread is decided, I identify with the losing side and give thanks that I didn't have to suffer three hours to lose my money. I listen to all my gambling friends' tales of woe, offer sympathy and silently congratulate myself on my own restraint.

A couple weeks ago, the Jets were getting 3 1/2 points from the Bills and were tied, 24-24, in the last minute. With 40 seconds left in regulation, the Jets turned over the ball near midfield, but even then bettors didn't have to worry since a Buffalo field goal couldn't beat the spread. Of course, the Bills threw a bomb while the Jets were employing man-to-man coverage; the defender fell asleep and Buffalo scored a touchdown. While people who had taken the underdog were contemplating hara-kiri, I called every gambler I could think of and said, "Boy, I'm glad I didn't have the Jets."

Two Monday nights ago, New England was favored by three points over Miami, and a local gambler named Harvey told me he liked the Dolphins enough to bet $1,000 on them. But after his team had won in overtime, 16-13, he informed me glumly that no congratulations were in order.

When regulation play ended in a tie, Harvey was feeling good, knowing that he was likely to win or tie his bet. Then his phone rang. His bookmaker, an obliging gentleman, informed him, "The line on the over time is pick 'em."

Harvey glanced at his television saw that the Patriots were about to kick off, and stalled for a few moments. When he saw the Dolphins pinned down at their 10-yard line, and realized that this field position probably would doom a team with minimal offense, he said hastily, "Give me five thousand on New England."

Of course, Miami threw that bomb and Harvey, having liked the Dolphins from the outset, lost $4,500. I listened to this tale of woe with genuine compassion, knowing that there but for the grace of God went I.