Three senior U.S. Senators today launched an attempt to end the six-month-old baseball strike with legislation that would partially repeal the sport's 73-year-old antitrust exemption. Players union head Donald Fehr lauded the bill, introduced by Senators Orrin Hatch (R-Utah), Daniel Patrick Moynihan (D-N.Y.) and Bob Graham (D-Fla.). They want to let players mount court challenges -- as is done in other industries -- when owners unite to set labor restrictions. Congressional leaders, including House Speaker Newt Gingrich, are opposed to enacting legislation to solve the strike. Gingrich and Senate Majority Leader Bob Dole (R-Kan.) are slated to meet tomorrow with federal mediator, W.J. Usery, who also has been trying to break the deadlock.