On the surface, Iran and North Korea could hardly be more different. The former is a Middle Eastern theocracy, its ideology based on a bellicose reading of Islamic scripture. The latter is Asian and atheist, its ideology, Juche, loosely rooted in Stalinism. But scratch the surface, and you'll find significant similarities. Both have "supreme leaders" whose power it is unsafe to question. Both are egregious violators of fundamental human rights. Both see the United States as their archenemy. Both pose proliferation problems from hell. Imagine a world in which both North Korea and Iran can wipe out cities in America or anywhere else. What concessions would be made to prevent such an eventuality? What gestures of appeasement would be offered? What tribute would be paid? Is there anyone -- Republican or Democrat, internationalist or noninterventionist -- who does not regard this outcome as contrary to the vital national security interests of the United States- Former U.S. President Barack Obama chose to ignore North Korea's nuclear weapons development. The euphemism for his policy was "strategic patience." But one can't say that his predecessors achieved more. Diplomatic initiatives have consistently led to dead ends. In 1994, then-U.S. President Bill Clinton concluded the Agreed Framework, intended to end North Korea's nuclear progress. Twelve years later, Pyongyang conducted its first nuclear test. Clinton's successor, President George W. Bush, attempted to negotiate a new and improved agreement. He failed. During the Cold War, we relied on mutually assured destruction to keep American and Soviet nuclear weapons in their silos. Is that doctrine adequate to constrain Kim Jong Un, a dictator whose grasp on rationality is difficult to gauge? What happens if Iran's next supreme leader believes that to bring about the return of the 12th Imam, the Shia messiah, requires an apocalypse? Bernard Lewis, the esteemed scholar of Islam, famously said that for those who hold such beliefs -- former Iranian President Mahmoud Ahmadinejad was among them -- "MAD is not a deterrent, but an inducement." It was two years ago this month that, with neither congressional nor public approval, Obama concluded the Joint Comprehensive Plan of Action under which Iran's rulers have agreed to temporarily halt a nuclear weapons program whose existence they have never acknowledged. Over time, restrictions on Iran sunset, meaning that if Iran's rulers exercise patience, the door to the nuclear weapons club will open to them no matter how extreme their ideology, hegemonic their ambitions or criminal their conduct. Meanwhile, they are developing intercontinental ballistic missiles that have only one conceivable purpose: to deliver the nuclear warheads they don't yet have to targets distant from the Middle East. Pyongyang is also working on ICBMs, and this month launched one that could hit Alaska. There is evidence to suggest that Iran and North Korea are cooperating in these endeavors. Keep in mind that in 2002, George W. Bush cited Iran, North Korea and Iraq as belonging to an "axis of evil." A strong argument can be made that Bush erred by deciding to do something about Iraq (which, it turned out, did not have an active nuclear weapons program) and nothing about Iran or North Korea (both of which did). Of course, we'll never know what would have happened had Obama not withdrawn all U.S. troops from Iraq in 2011, at a time when, according to no less an authority than Vice President Joe Biden, Iraq had "a stable government" that was "actually moving toward a representative government." At this point, U.S. policy options range from bad to worse. The U.N., as usual, is useless. This month, 122 non-nuclear U.N. members adopted a Treaty on the Prohibition of Nuclear Weapons to be signed at the U.N. General Assembly in September. This much can be predicted: It will have no impact on anyone or anything. This month, too, Russia blocked a Security Council statement drafted by the U.S. calling for new international sanctions in response to North Korea's latest ICBM launch. Why does Russian President Vladimir Putin defend Kim? The fact that North Korea poses a danger and a distraction to the U.S. may not be the only reason but it is reason enough. It would be comforting to know that the U.S. had an effective missile defense system in place. That might have been accomplished by now had it been on Obama's to-do list over the past eight years. The new administration should be moving on that full speed ahead. Crippling -- not just symbolic -- sanctions should be imposed on North Korea. Those doing business with North Korea need to be informed that they can no longer do business in the U.S. This will inflict additional pain on ordinary North Koreans. But the future of their children and grandchildren will be brighter following the fall of the Kim dynasty. North Korea is China's client. It needs to become China's problem. Changing that calculus requires imposing sanctions on China, giving consideration to putting tactical nuclear weapons in South Korea (they were removed in 1991) and encouraging Japan to become China's nuclear-armed neighbor. As for Iran, its ICBM program, continuing support for terrorists and other nefarious behaviors should lead to further sanctions as well -- such measures are not barred by the JCPOA. Finally, the supreme leaders of both Iran and North Korea should be given reason to worry that the U.S. has military options it can exercise -- options that could put a quick and surgical end to their regimes. If such options do not currently exist, developing them ought to be the Pentagon's highest priority. A United States that can be menaced and perhaps attacked by nuclear-armed fanatics should be unacceptable to all sensible Americans -- right, left and center. Clifford D. May is president of the Foundation for Defense of Democracies and a columnist for The Washington Times.