In attempting to analyze the outcome of a pro football playoff game, perhaps the best theory is the simplest: Go with the team with the better quarterback.
With that in mind, today's matchups in the NFL playoffs are Jake Delhomme of Carolina against Marc Bulger of St. Louis and Steve McNair of Tennessee against Tom Brady of New England, then Sunday it's Peyton Manning of Indianapolis against Trent Green of Kansas City and Brett Favre of Green Bay against Donovan McNabb of Philadelphia.
The two young gunslingers, Delhomme and Bulger, are a tossup. So are McNair and Brady, each tried and true. The more explosive Manning has to be the choice over Green, and the often fabulous Favre deserves an edge on McNabb.
Other factors can intrude, and will: cold, windy weather in Foxboro (where a wind chill of minus-15 is forecast) and in Philadelphia, injuries (the Eagles are without Brian Westbrook) and raise-the-roof rooters (especially in the Rams' dome).
But, eventually, all four games are likely to boil down to how well the quarterbacks play, as pro football games usually do, as last weekend's did.
Delhomme thoroughly outplayed Dallas' Quincy Carter. McNair was better than Baltimore's Anthony Wright. Favre didn't make any mistakes, while the one mistake by Seattle's Matt Hasselbeck, an overtime interception that Packers cornerback Al Harris returned 52 yards for a touchdown, lost what was a classic shootout. Manning's five touchdown passes overwhelmed Denver's Jake Plummer.
In this weekend's games, the most interesting, for historical as well as topical reasons, is the Packers-Eagles showdown.
Not only will Favre be trying to sustain the emotional theater of the Packers' three victories since his father's death, but Green Bay has not played the Eagles in the postseason in 43 years -- not since the 1960 NFL championship game at Franklin Field, an Ivy League fortress.
The Eagles won, 17-13, when linebacker Chuck Bednarik, also their center that day as the last two-way player in professional football, tackled Packers fullback Jim Taylor at the 8-yard line, then sat on him to keep him from getting up for another play as time expired. It was coach Vince Lombardi's only loss on his 9-1 postseason resume.
The quarterbacks in that game were Norm Van Brocklin for the Eagles and Bart Starr for the Packers. And for all of Starr's later success in leading the Packers to five NFL championships, including the first two Super Bowls, at that time Van Brocklin was better and more experienced.
This time the Eagles will be without Westbrook, their game-breaking running back and pass receiver, who also returned punts and kickoffs; he had surgery this week for a torn triceps muscle. Westbrook's absence puts the burden on Duce Staley and Correll Buckhalter, and the Eagles' defense will try to blitz and confuse Favre -- as Harris, the Packers' hero last Sunday, knows better than anybody.
Acquired in the off-season from the Eagles, where he was considered perhaps pro football's best nickel back, Harris explained the philosophy of Jim Johnson, the Eagles' defensive coordinator.
"In the Eagles' defense," Harris said, "it's 11 guys on the quarterback. Here in Green Bay, it's pretty much 11 on 11. With Jim, it's knocking down the quarterback, getting in his face."
But despite the burning memory of the Eagles' 17-14 victory at Lambeau Field on a Monday night in early November this season, don't expect Favre to have studied more film of the Eagles' defense or to have practiced harder or to approach this game more seriously than he approaches any other.