Energy issues have interrelated domestic and foreign policy aspects. I will discuss the national security implications of three critical energy issues: dependence on imported oil, the challenge of expanding the use of nuclear power worldwide without increasing the risk of proliferation of nuclear weapons, and global warming. Progress on each of these issues will not be easy, quick, or cheap for our society. Our energy future depends on managing these issues in the short term while beginning today the long term transition away from a petroleum economy.