WALHALLA, S.C. (AP) _ U.S. Rep. Lindsey Graham, one of the prosecutors during President Clinton's impeachment, announced Wednesday that he will seek the Republican nomination for the Senate seat being vacated by Strom Thurmond.

Graham, who was elected to Congress in 1994, often served as a spokesman for the 13 prosecutors in Clinton's impeachment. He also was active in last year's presidential campaign for Sen. John McCain, R-Ariz.

Graham said his campaign would emphasize national defense, Social Security and education issues.

Thurmond, 98, is the nation's oldest and longest serving senator. He has said he won't seek re-election next year. So far, no other Republican has indicated interest in seeking the nomination.

Possible Democratic challengers include Phil Lader, the U.S. ambassador to Great Britain and Lake City businesswoman Darla Moore.