On IN THE NEWS: An expert on the U.S. vice presidency discusses how the position has changed.

On IN THE NEWS: With the Democratic nomination secure, Barack Obama now faces work to unite the party. Will it mean he chooses Hillary Clinton for vice president?

On THIS IS AMERICA: The presidential campaign heads into the last six contests to choose a Democratic nominee. Also, short biographies of Barack Obama, Hillary Clinton and John McCain.

On IN THE NEWS: Barack Obama still has the delegate lead and financial security. But some supporters worry that he has been unable to cut into Hillary Clinton's base, especially white, working-class voters.

On IN THE NEWS: New York's governor built his political life on fighting corruption. He resigns after being identified as a client of a prostitution business.

On IN THE NEWS: John McCain secures the Republican nomination. New life in the Clinton campaign intensifies issue of re-votes in Florida and Michigan.

On IN THE NEWS: A look back at almost 50 years of Fidel Castro’s Cuba and its stormy relationship with the U.S.

On IN THE NEWS: With Mitt Romney out, John McCain urges party unity as Democrats remain without a clear front-runner.