Major League Baseball has always looked negatively at legalized gambling on its games, probably as a result of the illicit gambling that nearly brought the sport down in the Black Sox scandal in 1919.

But legal sports betting has gone on in Las Vegas for decades.

That's why this is a bit of a surprise:

Four U.S. professional sports organizations, including the National Football League and Major League Baseball, sued to block sports wagering in New Jersey, saying it would raise doubts about the integrity of games.

The leagues seek to block a law signed by Governor Christopher Christie in January that would permit gambling at racetracks and Atlantic City casinos on professional and college sports. The National Hockey League, National Basketball Association and National Collegiate Athletic Association joined the complaint filed today in federal court in Trenton.

The legal filing says that the leagues are concerned that:

“Sports gambling in New Jersey would irreparably harm amateur and professional sports by fostering suspicion that individual plays and final scores of games may have been influenced by factors other than honest competition.”

It's not clear why the leagues feel this would happen in New Jersey when it's not happening in Las Vegas and other places where sports betting is legal. The case was filed in federal court; if the court doesn't enjoin the state from beginning the sports betting, New Jersey would begin accepting applications for licenses starting at the end of this month.