It is understandable that Americans focus their attention on the Middle East. The media supplies a daily stream of news about America's continued war with the Islamic State, or ISIS. And the recent attacks in Europe and San Bernardino, have made terrorism a major issue in this year's election, whether initiated by Jihadists recruited from at home or abroad.
Poll numbers at the end of last year suggested that a majority of Americans think that President Obama is not taking the threat from ISIS seriously enough. They believe that an overwhelming use of force would end the threat. Indeed, a more recent poll suggested that a plurality of those questioned believe the U.S. is losing the war on terrorism.
But is this where Americans should be focusing their attention if they are looking for large-scale threats? As someone who studies security issues, I believe that a recent cluster of events - North Korea's missile and nuclear tests, China's uncharacteristic reaction and the comments of G7 officials - provides us with some clues.
Existential threats must be...well, existential
The fact is that ISIS does not pose what has fashionably been termed an "existential" threat to the United States.
The word existential is increasingly used by politicians and analysts with little regard for its meaning beyond a large-scale threat. But Ted Bromund, a foreign policy analyst at the conservative Heritage Foundation, offers this more comprehensive definition:
An existential threat is one that would deprive the United States of its sovereignty under the Constitution, would threaten the territorial integrity of the United States or the safety within U.S. borders of large numbers of Americans, or would pose a manifest challenge to U.S. core interests abroad in a way that would compel an undesired and unwelcome change in our freely chosen ways of life at home.
Clearly, Jihadism as an ideology can't do that to Americans. And despite the recent concerns expressed by President Obama, there is little chance that groups like ISIS can detonate a nuclear weapon in the U.S.
Even the admittedly terrifying release of a dirty bomb wouldn't kill casualties on a massive scale. As the U.S. Nuclear Regulatory Commission succinctly phrased it,
A dirty bomb is not a "Weapon of Mass Destruction" but a "Weapon of Mass Disruption" where contamination and anxiety are the terrorists' major objectives.
The very long struggle with North Korea
The American public, particularly Republican voters, may continue to focus attention on terrorism, but they should be focusing their attention on developments in North Korea. Arguably, the events unfolding there far more threatening.
The U.S. has a long and violent history of struggle with North Korea, dating back to the bloody war that took place in the early 1950s and cost 36,574 American lives.
The truce between the two Koreas was never concluded by a peace agreement. In defense of South Korea, the U.S. has been in a perpetual state of limbo ever since, caught between war and peace.
Most Americans either don't understand this or don't care very much, with only 16 percent of Americans polled naming North Korea as America's "greatest enemy" in a recent survey. But the North Koreans certainly do.
The Demilitarized Zone - a 148-mile-long strip of land that separates North and South Korea - is protected by 37,000 troops to its south and is home to over a million landmines. Indeed, the fact that the U.S. lays mines there is the primary reason often given for its failure to sign the 1998 Global Landmine Treaty.
North Korea is an impoverished country that has been propped up by China, its only major ally, since the end of World War II.
The Chinese don't want a reunited, more powerful Korea on their doorstep, let alone one allied to the United States. China is North Korea's biggest trading partner, and the Chinese have repeatedly provided diplomatic support to stave off the imposition of U.N. sanctions.
Comprehensive figures on aid or trade with North Korea are hard to find. But the U.N. routinely provides emergency assistance to stave off the occasional famine.
North Korea has been brutally ruled by 33-year-old Kim Jong-un for five years. He succeeded his father, Kim Jong-il, who led the country for 17 years.
To Americans, North Korea seems like a caricature of an evil dictatorship drawn in a Hollywood movie (as indeed it was, controversially, in the 2014 movie "The Interview").
It is one they only occasionally hear about, usually when an American foolhardy enough to visit there is detained on charges that baffle most Americans. The North Koreans then extort some prize in exchange for the prisoner's release. This usually involves the visit of a high-level dignitary to plea for clemency, as Jimmy Carter did in 2010.
Just this January, Otto Frederick Warmbier, a visiting American student, was detained in January on the grounds that he had committed a "hostile act" by allegedly removing a political banner from a hotel and was sentenced to 15 years of hard labor in March.
Is there a real North Korean threat?
To many Americans, then, North Korea seems an appalling place. But they regard it as distant, backward and relatively harmless.
They are wrong.
North Korea's leadership has seen - and still does see - the United States as its mortal enemy. And, unlike ISIS, it is developing into a viable one.
In 1993, a conflict over North Korea's proposed testing of nuclear weapons generated a crisis that almost resulted in a war. A deal was eventually struck with the U.N. But this just delayed the inevitable.
Unlike the Iranians, North Korea moved ahead and began testing nuclear weapons a decade ago, in defiance of a U.N. agreement. Since then, they have reputedly carried out four underground nuclear tests, the most recent being in January this year.
Skeptics have consistently suggested that there is a difference between causing a nuclear explosion and being able to miniaturize the technology to put it is a missile head able to reach the American mainland. But in the last few months, the North Koreans have launched a series of missile tests.
And on April 9 they claimed to have successfully tested an engine designed for an intercontinental ballistic missile.
This engine, they claim, would "guarantee" the ability of North Korea to launch a nuclear strike on the U.S. mainland. To emphasize the point, they also recently released a propaganda video depicting a nuclear strike on Washington.
Now that does sound like an existential threat.
It is anyone's guess if they have in fact figured out how to fit a nuclear weapon in a missile. South Korean officials suggest that it is a possibility. And it is just as unclear if they have developed a missile that can reach the U.S. mainland.
The fact is, however, that the North Koreans' bellicose behavior is making even their traditional Chinese allies nervous. China has now endorsed U.N. sanctions against its traditional ally. And - in a first - the two are engaged in an uncharacteristic public war of words, with Beijing staunchly opposing its ally's pursuit of nuclear weapons.
This behavior is scaring North Korea's other neighbors as well.
The concluding statement at the G7 foreign ministers' meeting in Japan this week condemned North Korea's nuclear and missile testing.
The next foreign policy crisis
Of course Kim Jong-un may just be adopting an aggressive posture in order to ward off an American preemptive assault. But, if that is the case, he is taking a very big risk.
If North Korea is approaching the point where it has a nuclear capability, then there will inevitably be those who call for a preemptive strike before they join the nuclear club.
It is one thing to be near having a nuclear weapon. It is another thing to threaten the U.S. Only the foolhardy would do both.
So is it time to reassess what really constitutes an existential threat to the United States?