Washington, D.C. ? President Barack Obama is breaking with the go-it-alone Bush years in a new strategy for keeping the nation safe, counting more on U.S. allies to tackle terrorism and other global problems. It’s an approach that already has proved tricky in practice.

The administration’s National Security Strategy, a summary of which was obtained Wednesday by The Associated Press, also for the first time adds homegrown terrorism to the familiar menu of threats facing the nation — international terror, nuclear weapons proliferation, economic instability, global climate change and an erosion of democratic freedoms abroad.

From mustering NATO forces for Afghanistan to corralling support to pressure North Korea to give up its illicit nuclear weapons program, the U.S. has sometimes struggled in leaning on friends and allies in recent years. Still, the new strategy breaks with some previous administrations in putting heavy emphasis on the value of global cooperation, developing wider security partnerships and helping other nations provide for their own defense.