LEXINGTON -- U.S. Secretary of Defense Robert Gates, the commencement speaker at the Virginia Military Institute today, urged the graduating cadets to commit themselves to public service, both as civilians and soldiers.

"We live in a time of great necessity, a time when we cannot avoid the burden of global leadership -- the stakes are too high," Gates told the 246 graduating cadets inside Cameron Hall. "It is precisely during these times that America needs its best and brightest from all walks of life to step forward and commit to public service, to exchange the life of ease and contentment and take on the burden . . . "

More than half of the graduating class -- 129 cadets -- were commissioned as officers in the nation's armed forces yesterday. School officials said others in the class will also join the military in coming months.

Gates praised the school's ability to provide officers and enlistees to the U.S. military, noting that 1,200 graduates have served in Iraq or Afghanistan and 75 had to put their education on hold after being called to active duty. He also paid tribute to eight graduates killed in Iraq and Afghanistan.

"If in the 21st century America is to continue to be a force for good in the world, for freedom, justice, the rule of law and the inherent value of each person, if America is to be, still, a beacon for all the oppressed, if America is to exercise global leadership consistent with our better angels, then the most able and idealistic of today's young people must step forward and agree to serve their country with the same honor and courage and dignity that marked the service of a long line of patriots that came before them."