The Cardinals Controversial 1925 NFL Championship
Based on their relatively unsuccessful franchise history, it seems particularly cruel for there to be a segment of the population (although small these days) that want to strip the Cardinals of their 1925 NFL Championship.
The Cardinals finished the 1925 season with the best record in the league and were set to play the Pottsville Maroons (a now defunct original NFL franchise) for the title. Pottsville had beaten the Cardinals 21-7 late in the season and were the odds on favorite to win the title. NFL teams had a lot more independence during those days and after their regular season was over, Pottsville scheduled a game against a team made up of Notre Dame All-Stars. This game was played in Philadelphia on the same day that the Frankford Yellow Jackets, a local NFL team, had a game scheduled.
Frankford filed a protest with the league and the commissioner (Joe Carr) warned Pottsville not to play. Pottsville claims that in a phone conversation later, Carr approved the game although the NFL would deny this claim. As punishment for going against a league ruling, the NFL suspended the Maroons from any official league involvement (including playing for the Championship) and eventually stripped the owners of the franchise. The Championship was then awarded to the Chicago Cardinals who successfully won it without having to play in a title game.
The Pottsville Maroons would go on to only play a couple more years before becoming the Boston Bulldogs for a year and then ceasing operations.
In 2003, the NFL considered reopening the case but voted 30-2 to let the Cardinals 1925 Championship stand.