One of the Republican Party's stars of the South predicted Monday that within 10 years the GOP will find it impossible to win the White House or either house of Congress unless it significantly increases its support among black and Hispanic voters.

"The big issue for the party has nothing to do with politics," Sen. Lyndsey Graham (S.C.) told Washington Post editors and reporters. "It's about race." (Listen to audio excerpts from Graham's meeting with The Post.)

The junior senator from South Carolina said President Bush will be reelected in November -- and win big in the South - but demographic changes in politically important states will force the GOP to broaden its appeal and boost the diversity of the Republican candidate pool to win in the future.

"You're sitting at the height of the Roman Empire for the Republican party," Graham said, "but the tide slowly but surely goes out." Graham, who in 2002 won the seat that belonged to Strom Thurmond for nearly half a century, said his party must make a concerted effort to reach out to African Americans and Hispanics to support the party and to run for office.

"It's not about how to get back to fiscal discipline or how you relate to the U.N.," Graham said, but hits closer to home. "It's how you relate to Americans who tell you to go to hell politically."

Graham said this November's race will hinge on three matters that are traditionally vital when a president seeks reelection: undecided voters' tendency to vote against the incumbent; the incumbent's job performance; and the challenger's ability to prove himself to be a viable alternative. Sen. John F. Kerry (D-Mass.) has failed to meet the third challenge, and that will be decisive, Graham said. The Democrat's weakness may be Bush's greatest electoral strength, he said.

Kerry "has a chance to turn it around, but he's running out of time," Graham said.