President, presidency, presidential

Capitalize as a title when it immediately precedes a personal name; otherwise lowercase, including appositives.

Avoid abbreviating.

President Barack Obama but U.S. president Barack Obama

President-elect Barack Obama; the president-elect

former president George W. Bush

then president Bill Clinton

president of the United States, the president, a president, his presidency

presidential powers

president of the Confederacy

President and CEO Gary E. Knell

president of the National Geographic Society, the president, his presidency

president of France, the president

Alice Jones, president of CBS; President Jones; the president of CBS