Take Super Bowl XLII, for instance. While the New England Patriots boasted the highest-scoring offense in NFL history and perhaps the game's best quarterback, everyone looked at the Giants' surging defense and hellacious pass rush and said, "that's nice, but ..."
The year before, the Indianapolis Colts won the Super Bowl with a statistically poor defense. But the healthy return of safety Bob Sanders gave the Colts a superb defense — which carried over into this season, when Indy ranked third in the league.
There's probably no greater example of what a great defense does than the 2000 Baltimore Ravens, who won Super Bowl XXXV with Trent Dilfer, for crying out loud.
Which leads us to the Packers.
The Packers have only one unrestricted free agent of note, and that's defensive tackle Corey Williams. The smart money says general manager Ted Thompson will let Williams depart for three reasons.
One, it's a weak free-agent crop of defensive tackles, meaning some team will offer Williams an inflated contract. Two, the Packers are deep at defensive tackle and have a lot of money and resources invested in that position. Third, there's always a danger in handing a player a big contract when his one and only strong season came as he took his first foray into free agency.
For those reasons, it makes sense for Thompson to let Williams sign elsewhere when free agency starts on Feb. 29.
But ... there are two big buts.
But No. 1: The Packers have a high-powered offense. With a young offensive line another year stronger and wiser, with Ryan Grant getting a training camp under his belt, with Mike McCarthy finding new ways to destroy defenses with his five-receiver sets, the offense should be even better next season. But can Brett Favre, who'll be 39 by midseason, continue defying age? And if he retires, it's almost impossible to imagine Aaron Rodgers coming off the bench and immediately posting a 4,000-yard, 30-touchdown season. So, a strong defense — no, a better defense — is a necessity if the Packers have designs on winning the Super Bowl next season.
But No. 2: The Packers' best position — until injuries struck — was defensive tackle, with Ryan Pickett joining Williams, Johnny Jolly and Colin Cole. The Packers were so deep that first-round pick Justin Harrell couldn't get on the field for most of the season. The assumption is Harrell will take a big step forward — just like Jolly did between 2006 and 2007 — and Jolly will come back strong from a season-ending shoulder injury. But those are assumptions, not guarantees. With Williams — assuming he doesn't turn into Cletidus Hunt after signing a big contract — you know what you've got.
Defense wins championships, and a strong defense starts with the defensive line, because that unit can either mask or amplify a team's strength or weakness. Look at the Giants, whose pass rush helped a suspect secondary shut down the high-powered Packers and Patriots offenses.
When Cole and, especially, Jolly went down, the Packers' defense went from very good to merely good, and that's not good enough.
The Packers enter the offseason about $25 million under the salary cap, and they'll gain another $3 million or so if they part ways with tight end Bubba Franks. The Packers are in this position because they've managed the cap wisely by not overpaying for players and not putting too much money into one position.
Logic probably dictates the Packers stay the course, refrain from designating him their franchise player (meaning a one-year, $6.263 million tender) and let Williams go if he gets too big of an offer. But — there's that word again — the Packers are on the precipice of doing something special. Now's not the time to be losing quality players.
Steve Lawrence is a regular contributor to PackerReport.com. E-mail him at firstname.lastname@example.org