The cap makes the rule unnecessary. If you already have a cap, the rule is just a pointless addition to make it more difficult to improve your team. A hard cap would make the rule unnecessary. The NBA uses a soft cap. Did you read CubColtPacer's post? Yes, I just don't see how it's true. Obviously it hasn't kept good teams from being dominant, as the same teams keep winning. Not allowing teams to trade actually pretty much guarantees that bad teams will stay bad and great teams will stay great. But I guess this is the closest anybody has come to supplying a reason for the rule. It's not like the NBA is the only league with foolish rules. It just seems to me that most leagues have these rules set up for a legit reason to benefit either the teams or the players. If you have a salary cap and then tax every dollar spent above that cap, then why can't they just tax the added dollars that come via a trade? It's not like teams are just going to be giving away Kobe Bryant and Allen Iverson type players to the dominant teams and not take market value back. It appears to me to be an unnecessary barrier to trade. A man-made inefficiency that doesn't help anybody. A lawyerly creation designed to look smart but in practice and in reality, without purpose. The NBA is still a team dominated by the teams that win in the draft. It takes teams forever to get any good. More ability to trade would allow the better GMs to go from have nots to haves in a more timely fashion. The current system just seems to doom the bad teams to poisoning their home market. The NBA has just as much fluctuation from bad to good as any other league. You have your 5-6 teams at the top (where 1 team breaks in about every year) your 16-18 teams in the middle, and then your 6-8 teams at the bottom with terrible management. Here are the teams in the NBA who have won at least 50 games in the past 5 years (good teams): Detroit, Cleveland, Dallas, Phoenix, San Antonio, Houston, Utah, Miami, Seattle, Sacramento, Indiana, Minnesota, LA Lakers, Memphis, Portland. That's half the league right there-and that doesn't include the Nets (who were in the NBA Finals during that stretch), the 76ers (who were in the finals in the 2000-2001 season and were good as recently as 4 years ago), the Bulls (who won 49 games this year after being bad 5 years ago), the Wizards (who were a tough out in the playoffs last year), the Bucks (who won 51 games 6 years ago and were in the playoffs 3 out of the past 5 years), Denver (who has been in the hunt for several years including winning 49 games one year), and several other examples. It's not harder to go from bad to good or good to bad in the NBA-the only thing that makes winning championships harder than other sports is the best of 7 rule. In other sports, the best team doesn't win most of the time, but in pro basketball it does, and that's why you'll see less champions overall. There have been plenty of very good teams though.