Rice praises Obama win in Democratic race

President George W. Bush speaks about the benefits of his 2003 tax relief act in Washington June 2, 2008.

WASHINGTON (Reuters) - Secretary of State Condoleezza Rice said on Wednesday Barack Obama's emergence as the first black American to win a major party's presidential nomination was a landmark for equal rights after more than two centuries of struggle.

Rice is the top-ranking African American in the Bush administration and has often spoken about the struggles of fellow black citizens who were subjected to slavery or segregation for much of U.S. history.

She has been mentioned as a potential running-mate for Republican John McCain but has repeatedly said she is not interested.

Obama, a Democrat, is the first African American to be nominated by one of the major parties for the White House.

"It's a country that has overcome many, many, now years, decades of, actually a couple of centuries, of trying to make good on its principles," Rice said.

"And I think that what we're seeing is, an extraordinary expression of the fact that 'we the people,' is beginning to mean all of us," she added, referring to the opening line of the U.S. Constitution.

Obama clinched the nomination over rival Hillary Clinton after the last of the state-by-state nominating contests on Tuesday and will face McCain in November's presidential election.

At the White House, Republican President George W. Bush offered congratulations for Obama's "historic achievement" in securing the Democratic Party's nomination, spokeswoman Dana Perino said.

"He knows from personal experience nominating process is a grueling one and Sen. Obama came a long way in becoming his party's nomination," said Perino.

(Reporting by Susan Cornwell and Jeremy Pelofsky, editing by Frances Kerry and Alan Elsner)