WASHINGTON--Senate Republican leader Trent Lott tried to help Bob Jones University keep its federal tax-exempt status despite the school's policy prohibiting interracial dating two decades before his recent comments stirred a race controversy. 
''Racial discrimination does not always violate public policy,'' Lott, then a congressman from Mississippi, wrote in a 1981 friend of the court brief that unsuccessfully urged the U.S. Supreme Court to stop the Internal Revenue Service from stripping the university's tax exemption. 

The old court filing surfaced on a day when Lott tried to quell criticism, fueled by Democrats, over remarks he made at a birthday party last week for 100-year-old Sen. Strom Thurmond (R-S.C.). Lott had suggested the country would have been better off if Thurmond, running for president on a pro-segregationist ticket in 1948, had won. 
White House officials said President Bush found the remarks indefensible but said they expected Lott to weather the storm. 

Making the rounds on television news shows, Lott said Wednesday his comments were a ''mistake of the head and not of the heart'' and added that ''the words were terrible, and I regret that.'' 
Bob Jones University is a fundamentalist Christian school in Greenville, S.C., that long stirred controversy with its racial policies. 
Democrats on Wednesday called for Lott's resignation as GOP Senate leader. 
''I simply do not believe the country can today afford to have someone who has made these statements again and again be the leader of the United States Senate,'' said Sen. John Kerry (D-Mass.), one of several potential 2004 presidential candidates to weigh in against Lott. 
No Republican senator has called for Lott to step down from the majority leader post he is to take over next month. 
But the four Republican appointees to the U.S. Commission on Civil Rights issued a joint statement deploring Lott's comments as a ''particularly shameful remark coming from a leader of the Republican Party, the party of Abraham Lincoln, and the party that supported all of these essential steps forward far more vigorously than did the Democratic Party, which at the time was the home of congressional Southerners committed to white supremacy.'' 
The Jackson Clarion-Ledger in Mississippi reported Wednesday that Lott made a statement very similar to last week's when he appeared with Thurmond at a rally in Jackson, Miss., on Nov. 2, 1980. 
Meanwhile, Rep. Jan Schakowsky (D-Ill.) called on Sen. Peter Fitzgerald (R-Ill.) to urge Lott to step down as a Senate leader and "speak out" about Lott's remarks. 
Fitzgerald said he will continue to support Lott. 
"It is my hope that you will put American values and common decency above politics and condemn Sen. Lott's reprehensible behavior," Schakowsky said. 
Fitzgerald replied, "I don't believe that Sen. Lott's remarks were intended in the spirit in which it was interpreted." 
Contributing: Lynn Sweet