Military spending, a nuclear arms race and a growing threat of cyberwarfare are dominating the national security agenda in 2018. With U.S. troops engaged in combat in Syria, Afghanistan and elsewhere, Congress in February authorized the Pentagon’s largest budget ever. Cyberattacks, meanwhile, are growing. A new Defense Department document declared that “strategic competition [among nations], not terrorism, is now the primary concern in U.S. national security.” The government itself is divided over which nations are of concern, however, as President Trump questioned assessments that Russia targeted the U.S. election in 2016. And nuclear arms races escalated as North Korea tested long-range nuclear weapons; Pakistan, India and China expanded their nuclear programs; the United States and Russia continued to modernize their arsenals; and Trump pulled the U.S. out of the 2015 Iran nuclear agreement.