Marc Tracy of Grantland (hat tip: Knockoutking of Lone Star Ball) has a nifty piece on the history of the Cowboys-Redskins rivalry. Very much worth a read as you get pumped for tonight's game.
Of particular interest, he starts off with this:
I have a theory as to what the National Football League's greatest rivalry is, but I need to know what the NFL itself would say. So I call NFL Network's Mike Lombardi and ask him. Lombardi possesses an unmatched system of alliances (he has worked for everyone from Bill Walsh to Bill Belichick), an ability to seamlessly do-si-do between the executive and press boxes, and an uncanny penchant for spouting the smartest strain of the moment's conventional wisdom. In short, Lombardi is the David Gergen of the NFL. His answer will be definitive. He pauses for quite some time. Finally, he comes out with it:
He also gets Ernie Accorsi and Greg Aiello to agree. Despite the teams being mediocre, more or less, for some time, they all consider the Cowboys and Redskins to be the biggest rivalry in the NFL, even today.
This shouldn't be too much of a surprise, of course. More goes in to a rivalry than teams simply being actively good. As Accorsi mentions in the article, and as Tracy spends his whole time discussing, there is a rich -- and successful -- history behind these teams. Also important is popularity
You can argue all you like about the term "America's Team," and whether it should be applied, but it would be just about impossible to argue that the term could be applied to anyone if it can't be applied to the Dallas Cowboys. They consistently rank as the most popular, most watched, most valuable, and most buzzed team in professional football. Other fans have a right to be annoyed by that status -- heaven knows most of us baseball fans are annoyed by the Yankees for the same thing -- but it's the truth, and it's an important aspect to the rivalry. And with fans driven to hating the Cowboys by their omnipresence in the media and large, mouthy fanbase, you get a legion of fans who just want to see Dallas lose. When Cowboys and Redskins is the prime time game, that means a legion of temporary Redskins fans.
The Redskins rank pretty well themselves by every measure. Though Dan Snider has damaged their popularity, they're still in the top half of the league by Harris polls, they still ranked as Nielsen's 11th most buzzed team in the off-season, and ranked as Forbes's second most valuable franchise. Meanwhile thanks to Jerry World, when the Cowboys and Redskins play, you are matching the top two teams in attendance from each of the past two seasons.
The Giants, Eagles, Bears, Patriots, and Colts have all had more successful recent histories, but without the value and popularity the Cowboys and Redskins maintain, and without the deep history they've built together, they will likely have a tough argument for being called a part of the NFL's greatest rivalry.
Or you could just argue about what "greatest" means in this case. That, too.