NEW ORLEANS, FEB. 16 -- The Republican Party today rolled out its big guns, President Bush and former president Ronald Reagan, to try to keep David Duke, a former Ku Klux Klan leader, from being elected to the state legislature Saturday as a Republican. Letters touting Bush's support for Duke's opponent in the race were circulated throughout the district, while Reagan's endorsement was heard in radio commercials broadcast throughout the day. "I can't help but tell you of the high regard I have for one candidate in the race for the 81st district -- John Treen," Reagan said in the radio spot for the conservative house builder and longtime Republican. Treen, 62, and Duke, 38, a former Klan grand wizard, are in a runoff to represent the nearly all-white district in Metairie, a New Orleans suburb. Duke, who sought the 1988 Democratic presidential nomination but registered Republican in the fall, led a field of seven candidates with 33 percent of the vote in the primary Jan. 21. Treen had 19 percent. Bush and Reagan did not mention Duke specifically, but state and national Republican officials made it clear that a Duke victory would harm the party. "It's as if Attila the Hun joined our party," state GOP Chairman William Nungesser said. "All of a sudden Attila the Hun is a Republican candidate. I don't believe he's changed one bit." Leslie Goodman, spokeswoman for the Republican National Committee in Washington, said Duke "is not a Republican and should not pass himself off to be a Republican. We can tolerate a lot in this party, but the one thing we cannot tolerate is intolerance."