Cox, 58, married Tricia Nixon at a ceremony in the White House Rose Garden in 1971. He is a partner in a Manhattan law firm and a member of the State University of New York board of trustees, appointed by Gov. George Pataki.

The adviser said Cox, who has never run for public office, would not seek the Republican nomination if either Pataki or former New York Mayor Rudolph Giuliani decided to do so. Neither is expected to seek the Senate seat, and both are potential 2008 presidential candidates.

Cox was unavailable to comment because his mother died this week, the friend said.

Clinton, who easily beat then-Rep. Rick Lazio in the 2000 Senate race, is also considered a potential 2008 White House contender. New York Republicans have made it clear they would like to short-circuit that possibility by beating the former first lady in the 2006 Senate race.

Several state-level Republicans have expressed interest in the race.

© 2005 The Associated Press

Editor's note: