Tuesday's filing was expected after a federal judge last month declined New Jersey's motion to dismiss the lawsuit filed by the NFL, the NHL, the NBA, Major League Baseball and the NCAA.
The state had argued that the leagues and the NCAA, college sports' governing body, couldn't prove they would be harmed if it allowed sports gambling since all enjoy unprecedented success despite the existence of legal wagering in Nevada and more widespread illegal sports gambling.
Now, the focus will turn to the Professional and Amateur Sports Protection Act, a 1992 statute that prohibited sports gambling in all but four states: Nevada, where bettors can gamble on games individually; and Oregon, Montana and Delaware, which were allowed to offer multi-game parlay betting.
Attorneys for New Jersey claim the law usurps the authority of state legislatures and treats the states unequally by grandfathering in some states where sports betting already was allowed.
The leagues' attorneys have termed the constitutional challenge "specious" and have argued that the Constitution's commerce clause doesn't require uniformity in its application to different states. They referred in one court filing to Republican Gov.
In Tuesday's filing, lawyers for the Department of Justice asked U.S. District Judge Michael Shipp to give them until the end of next week to file responses to the state's constitutional challenges. Oral arguments in the case are scheduled for Feb. 14 in Trenton.
The leagues and the NCAA sued last summer after Christie signed a law that would allow sports wagering at Atlantic City casinos and the state's horse racing tracks. Games involving New Jersey colleges or college games played in New Jersey would be exempted.
Two months after the lawsuit was filed, the NCAA announced that several championship events scheduled to be held in New Jersey this year would be moved out of the state.