In March, Republican presidential candidate Mitt Romney called Russia America's "No. 1 geopolitical foe," following up on his December complaint that Vladimir Putin is "a real threat to the stability and peace of the world." But in February he was warning against the risks posed by China's "prosperous tyranny." In March, it was nuclear North Korea, one of the "world's worst actors." Back in 2009, Romney wrote an op-ed calling Iran "the greatest immediate threat to the world since the fall of the Soviet Union, and before that, Nazi Germany," while in 2007 he called jihad "this century's nightmare."

Romney, of course, is not alone. Republican presidential contender Newt Gingrich similarly offered up the nearly hysterical assertion that Venezuelan President Hugo Chávez's "anti-American" alliances with Iran and within Latin America could present the biggest threat to the United States since the Soviet Union. (To be fair, it's worth noting that during the 2008 presidential campaign, Barack Obama also called Cuba and Venezuela "enemies.")

Of course, there are problems even with the more credible of these assertions. Putin may be anti-democratic, a troublemaker with a very misguided sense of how attractive his bare torso is, but his country is a shell of its Soviet self. Russia is in the midst of a demographic meltdown pretty much unprecedented since the Black Death, and the country is even sometimes cooperative with the United States on issues from nuclear weapons reduction to counterterrorism. China may be a rising power that often disagrees with the United States, but the two countries' economies are deeply interdependent. China has little history of global adventurism, and though it is a large country with a large economy, it is also still a very poor one focused on its own social problems. As for the Islamic fundamentalists, they fall into two categories: private actors who are dangerous but small (al Qaeda) and state actors who are dangerous but middleweight (Iran). They pose threats. They may view America as the enemy. But they are not big enough or organized enough to warrant organizing America's entire foreign policy around them as the country did during the so-called "Global War on Terror." The true damage they might inflict on the United States, while serious, is limited.