U.S. President Barack Obama told West Point's graduating class Saturday the country must play a leading role in building international alliances. "The international order we seek is one that can resolve the challenges of our times," Obama said, including countering violent extremism and insurgency, stopping the spread of nuclear weapons and securing nuclear materials, preventing conflict, helping poor countries feed themselves and care for their sick and fighting global warming. "If we are successful in these tasks, that will lessen conflicts around the world," the president told about 20,000 people at the academy, on the Hudson River north of New York City. "It will be supportive of our efforts by our military to secure our country. We must pursue a strategy of national renewal and global leadership," he was quoted as saying by the United Press International (UPI).