There was a moment when Gregg Williams saw his perfect definition of beauty. It came in the first quarter last Sunday at FedEx Field, on the Redskins' first defensive series against Oakland. On third and eight from his 13-yard line, Kerry Collins took the snap and drifted back. He looked left, toward Randy Moss, cocked and prepared to throw to one of the most feared wide receivers in the NFL.

As soon as he raised his right arm, Collins felt sharp resistance at his elbow from linebacker Chris Clemons, who forced an errant throw. The doomed pass wobbled downfield and landed in the arms of another Redskins linebacker, Lemar Marshall, who charged 17 yards for a touchdown.

For Williams, the Redskins' assistant head coach-defense, this was exactly the kind of execution that justifies his almost steadfast belief in a blitzing defensive system that stresses unpredictability as much as pressure, discipline as much as instinct. An outside speed rush created chaos on the offensive line while disrupting the quarterback's delivery, and Collins, pressured quickly by Clemons, couldn't locate Moss and hurried his throw toward Marshall, well positioned for success. The scheme created pressure from the right side, maintained its discipline on the left and produced an ideal result.

It was the type of play expected to define Redskins football this year after the defense finished in the top five in several categories last season.

It was an extension of the reputation Williams had earned in Buffalo as head coach and in Tennessee as defensive coordinator. It is why Williams is expected to be at or near the top of a short list of potential head coaching candidates at season's end.

But with six games left in the season, the Redskins' defense at times remains in search of itself. For every Marshall touchdown or Ryan Clark interception near the goal line, the Redskins have surrendered bigger plays, such as Reggie Brown's 56-yard touchdown catch for Philadelphia and Edell Shepherd's 30-yard touchdown reception for Tampa Bay, which led to the winning two-point conversion.

Last season, the Redskins' defense gave up one play longer than 50 yards -- an 80-yard pass from Eagles quarterback Donovan McNabb to Todd Pinkston on Dec. 12. This season, the defense has allowed seven plays of 50 yards or more. It also has allowed four additional plays of 40 yards or more, the last being a key 49-yard touchdown from Collins to Jerry Porter on Sunday.

Against the Raiders, the defense was at times spectacular, evidenced by Collins's 14.0 passer rating in the first half and the Raiders' 1.7-yards-per-rush average. The Redskins rank 12th in passing yards allowed per game, but because of the number of deep passes permitted, they are 21st in average yards per pass. Moreover, few teams could even consider making the playoffs with the fewest forced turnovers, but the Redskins are squarely in the hunt.

The result is a sort of unevenness this season to the Redskins' defensive personality, and Williams and his staff have been faced with two simple but crucial questions. The first is whether offenses have discovered important keys to beating the Washington defense, if not consistently then for momentum-changing plays. The second is potentially more distressing, that the Redskins do not have the personnel to execute Williams's aggressive style to peak performance.

"You can only be who you are, and Gregg Williams is an aggressive, come-after-the-quarterback type of coach and defensive coordinator. So he can't all of a sudden one week be real vanilla and play it safe. If he does, then his defense will be worse," said Phil Simms, the former New York Giants quarterback whose son, Tampa Bay quarterback Chris Simms, passed for 279 yards and three touchdowns two weeks ago against the Redskins.

Williams and his staff must determine whether the cause is primarily injuries to Sean Taylor, Cornelius Griffin and Carlos Rogers, or if they overestimated the ability of their players and need to acquire more impact-style players next season. The question is apparent in the lack of pressure generated by the Redskins' front four, especially without tackle Griffin, who has missed the last three games and is questionable for today's game against San Diego. If it wasn't anticipated early in the season, it has become clear that a top priority for the offseason will be a defensive end who can pressure the quarterback.

"The mark of a good coach is to be able to adjust to what we have," Williams said. "And we haven't even been close to playing with what I expected us to play with. Sean Taylor has been out there, but he hasn't been close to playing healthy. We haven't had Cornelius Griffin, and LaVar [Arrington], we're just getting him back now. I honestly believe that along with Bill Belichick up in New England, we do it the best.

"This year, we're playing better teams, better quarterbacks. A lot of people want this to be a video game, to move a player here, put another one there," Williams said. "But there is a human part to every game. As soon as we looked on the schedule, we saw that every quarterback we faced had the chance to be better than the ones we faced the previous year. Combine that with what we've faced in terms of injury, and you have a different dynamic."

Beyond the crunching of the numbers is a growing sentiment around the league and also among some Redskins players and coaches that the team is rapidly approaching a crossroads. The Redskins are still ranked in the top third of the league defensively, yet have been susceptible to big plays, especially in the fourth quarter.

"Here's the thing," cornerback Shawn Springs said after Sunday's loss to Oakland. "We're not good enough to give up any big plays. All it takes is one or two. We give up that big play, and we lose."

Of the last 21 plays of 27 yards or more the Redskins have allowed, 13 have come in the last five games, and while the coaches do not believe the big-play susceptibility to be a sign of exposure, the defense has sounded a familiar refrain: quarterbacks look as if they know what's coming. Offenses have chosen to max protect, shorthand for the maximum protection formation. Randy Thomas, the Redskins' right guard, remembers facing Williams's Buffalo defense as a member of the New York Jets, and the mantra always had been to max protect.

"It was always confusing, because Gregg never did the same thing," Thomas said. "You thought you had something going, then you looked and they held you under 200 yards. Sometimes we only sent one or two guys out in the pattern."

That means the offense is anticipating a blitz and sends fewer receivers into pass patterns in favor of more blockers. "Anyone who was watching the game closely saw that they were protecting with everyone but their mama," defensive end Renaldo Wynn said of the Raiders in the second half, when Collins threw for 236 yards and a touchdown. "That's what teams are doing against us. They leave everyone back in max protect and leave it to the quarterback to find the spot."

In such a formation, both the offense and defense can claim an advantage. The offense will have enough blockers to find and contain the blitzing defenders, while the defense has fewer receivers to cover.

"If you've got a good, steady quarterback and a smart center, they're going to have an idea," Arrington said. "They might not necessarily know exactly where the pressure is coming from, but they'll know something. Whether you can stop it or not when we're coming, that's the whole thing."

Over the past two weeks, the advantage has gone to the offense. Springs has no sacks and no interceptions. Cornerback Walt Harris has been a target against the blitz. No Redskins cornerback has recorded an interception this year. Arrington has no sacks.

Against the Bucs, Simms recognized the blitz from the linebackers and cornerbacks and challenged the Redskins to stop their wide receivers one-on-one. It was against the Buccaneers that Williams was demonstrably upset by how his team responded to his teaching. He had instructed his secondary not to be beaten by balls over their heads, and yet 169 of Simms's 279 yards came on five backbreaking passes, all of 24 yards or more. The final was a 30-yard touchdown from Simms to Shepherd with 54 seconds remaining.

"Gregg Williams's teams are going to bring a lot of pressure. He has a formidable defense, and with the blitz, you know you're going to get your [butt] kicked," said CBS analyst Boomer Esiason, a former NFL quarterback. "But you also know you're going to get big plays, especially if there's no pressure from the front four. The D-line is the heart and soul of any defense, and without pressure, you're leaving yourself susceptible."

Over the past two weeks, it became clear to Williams that the difference between making plays and giving up big ones stemmed from the technique of his secondary.

It was against Tampa Bay that Williams, who considers himself more of a teacher than a coach, seemed frustrated by his players' execution. He responded by teaching more. What he began to see was his secondary failing to recognize the difference between a receiver's routes and his moves -- the feints, fakes and shifts that attempt to keep a defender off-balance. It was, said safeties coach Steve Jackson, a critical distinction.

"If you treat them the same, you'll be behind every play," he said. "If you can recognize one over the other, that a receiver is making one move to set up another, then you'll be able to be a more aggressive player."

The combination of falling for moves and not recognizing routes in the secondary, combined with the lack of a pass rush and offenses adopting max protect, has created the opportunity for big plays that did not exist a season ago.

Nevertheless, Redskins coaches do not believe the defense has been solved. As proof, Coach Joe Gibbs points to the Redskins' overall defensive rank, which despite obvious cracks during this 2-5 stretch, is ninth in the league. Defense was not the culprit in last week's tight loss to Oakland; however, it wasn't particularly stout when the Raiders mounted the game-winning drive. Against the Raiders, the defense yielded 16 points. In four previous games this year, the Redskins were unbeaten when giving up fewer than 18.

"What I'm proud of is that no one has done anything consistently to us," Gibbs said. "It's very difficult to be a top-10 defense with all the talent in this league."

Through the first seven weeks of the season, the Redskins had not given up consecutive 100-yard games rushing or receiving and had not surrendered consecutive 250-yard passing games. It was on this point that Williams appeared bolstered. "We're going to make you one-dimensional," he said. "The first thing we will do to you is take away the running game. If you're going to make yardage against us, it will have to be in the passing game."

During the last three games, McNabb, Simms and Collins each has passed for at least 279 yards, and two wide receivers, Joey Galloway and Porter, caught passes for 131 and 142 yards, respectively.

In the end, the worst scenario for Williams appears to be if he resigns himself to the belief that this season will be one where he never quite attained the personnel mix to be consistently effective. He says he hasn't reached that point, that his issues, and by extension the defensive leaks, are the byproduct of recognition, of reaction, elements he believes can be repaired by repetition and teaching.

"I think the big thing with Washington is, are they physically capable of carrying out what they are doing?" Phil Simms said. "Can they be so aggressive and continuously challenge the other team? And can they keep getting away with it?"