Obama, in final UN speech as president, calls for world course correction

UNITED NATIONS -- President Barack Obama conceded Tuesday that the United States and other world powers have limited ability to solve the most profound challenges facing the world, while calling for a "course correction" for globalization to ensure that nations don't retreat into a more sharply divided world.Obama, in his final speech to the U.N. General Assembly, acknowledged that the extremist and sectarian violence wreaking havoc in the Middle East and elsewhere "will not be quickly reversed.