By penalizing Bobby Unser a lap and making Mario Andretti winner of the Indianapolis 500, the United States Auto Club has done a fool's work.

USAC says videotapes show Unser broke a rule by passing slow cars during a caution period. Unser, incommunicado, had not contested that. After the race he said he entered traffic routinely, the same way he always has, running on the apron until he finds a spot to blend in.

The Indianapolis brass says there is a certain spot, designated by an orange marker, where drivers are expected to enter traffic behind the pace car. Unser, the 500 poohbahs now say, went far past the marker before getting in line.

So Unser broke the rule.

And he should be penalized.

But not the next day.

Judgment calls must be made on the spot. Had Unser been penalized immediately and force to wait in the pits one lap, it is very likely he would have made up that distance and still won the race (an explanation later).

To penalize Unser the next day gives him no chance to make up the penalty with his ability. Such a postfacto penalty is so grossly unfair it will be an upset if Unser does not take USAC to court.

Which brings up USAC's further crime: the opening of a can of instant-replay worms.

Wisely, the National Football League has avoided the use of videotape to make officiating decisions. Several times, in public flagellation Pete Rozelle has admitted that instant replays confirmed his officials blew calls. Not once, though, has the NFL reversed a judgment call on the basis of videotape. Not once has a victory earned on the field been denied in a hearing room.

Part of the NFL rationale for ignoring the obvious help of videotape is that examination of one play could lead to examination of another . . . and another, ad infinitum. If the Houston Oilers insist Mike Renfro has possession before he left the end zone, might not the Pittsburgh Steelers insist Dan Pastorini came over the line of scrimmage before throwing? And, look at this, Mr. Rozelle, three Oiler linemen are holding on the play.

Judgment calls must be made on the spot, and those judgments must not be subject to review by film. In golf, a player's unfortunate collisions with fate, such as a nice shot hitting a rake handle and falling into a cavernous trap, are passed off as "rub of the green, old-chap."

It is, less elegantly, just the way the cookie crumbles.

So the officials didn't catch Bobby Unser in the act. So what?

Just the way the cookie crumbles, Mario.

We soon will explain how Unser would have won even if penalized a lap. First, some recapitulation. . .

As he spoke with reporters immediately after the 500, Andretti said he left the pits with Unser after a stop under yellow on the 149th of the race's 200 laps. Instead of "blending in," as the rules demand, Andretti said Unser "just went on his merry way and passed four cars."

But no official called Unser on it.

Two hundred times at Indy, maybe 300 times, a racer's "blending in" is the subject of a judgment call. Thirty-three cars will make nine or 10 pit stops in the day. The call is not easy, because even under yellow the racers "blend in" at 80 miles per hour and so might have to slip in front of a car they ought to be behind. The track's patrol judges takes this difficulty into account when assessing a driver's maneuvers.

By most accounts, Unser's move was blatant. Andretti's teammate, Gordon Johncock, said Unser passed six cars, maybe seven. "I saw the whole thing," Johncock said, "because I was one that got passed."

Incompetence seems the likely explanation for the no-call.

Andretti: "I'm just disappointed it wasn't seen right away. They have people who get paid to watch for those things. It should have been an automatic penalty right there if they were on the ball."

Had officials done the right thing at the right time, they would have called Unser back to the pits and made him wait a lap before racing again. That would have put him one full lap behind Andretti with 50 laps to go.

No big deal. Unser would have caught him easily. And won the race anyway.

Unser's recorded margin of vicory, 5.3 seconds, is misleading. He figuratively coasted the last 15 laps, letting Andretti close a 14-second deficit that could have been 30 if Unser wanted it to be 30.

Unser's car, near the end, was almost a second a lap faster than Andretti's.So if Unser had been penalized a lap, and if they ran those last 50 laps at full speed, Unser would have passed under the checkered flag right on Andretti's tailpipe -- a very close second-place finisher.

But wait.

They didn't run those 50 laps flat out. There were four yellow-light periods. Under USAC rules, the cars bunch up under caution. A car 40 seconds behind at 190 mph, say, can close that two-mile gap to maybe a quarter-mile when the cars slow down and form a single line at 80 mph.

Clearly, Unser would have been on Andretti's tailpipe by the end of the second caution period at Lap 165.

Now, listen to Andretti's confession of inferiority. To force his car to keep Unser in sight, Andretti said, "I drove all over the place." And Johncock said of Unser, "I doubt if I could ever caught him."

So if Unser moved onto Andretti's tailpipe at Lap 165, he would have won the 500 going away.

Oh, yes. Unser's car owner, Roger Penske, has filed a protest of his own against yesterday's USAC decision. Penske says Andretti also broke the rule about "blending in" when he passed one car.

You can see it on the tape, Penske said.