Throughout history, countries have come and gone, some by their own hand, some by others. There is no other way, either suicide or murder. In the final analysis, this issue hovers over any and all discussion and debate on the future. National Security is just that: "national" and not partial or selective.
Even implicitly, the current debate between President Trump and the "resistance," be it political or the media, involves the ultimate question: will the country survive this administration? In some ways, it amounts to "total" war, reminiscent by many of the period before the Civil War itself.
There is no need to bring up the evidence, it can be seen daily and nightly, in the press, on talk shows, in the annual Correspondents' Dinner (that Trump has boycotted), in sports, in theater, on the subway, on bumper stickers and, in short, everywhere people "congregate."
The issue is apocalyptic and is couched that way. In other words, it is "existential." The full story can be summarized by the daily reminder on the top of page one of The Washington Post, "democracy dies in darkness." That says it all, but it remains uncertain as to who is putting out the lights (the media thinks Trump is, while Trump thinks they are).
Many think that Europe itself committed "suicide" in World War I. One of the most prophetic statements in history was made by the British Foreign Secretary, Edward Grey, as he was drafting his war message in 1914. Turning to his staff, he proclaimed "The lamps are going out all over Europe, we shall not see them lit again in our lifetime." Grey was correct but probably didn't realize that he was one of those blowing out the candles.
By geopolitical definition, the threats to American sovereignty/integrity have generally arisen from within. The great Civil War was by far the worst time in U.S. history, where 2.5 percent (720,000) of the population died, almost all white, male soldiers (more from disease than bullets). The closest external threat came in World War II, but even this is fanciful. Japan had no intention or capacity to invade the west coast. Pearl Harbor itself was meant to force an armistice to allow them to occupy China and the south Pacific. While German bombing killed tens of thousands throughout continental Europe and England, Japan's efforts to "balloon bomb" America killed a grand total of six people (a family in Oregon).
Regarding Nazi Germany, the U.S. may have never declared war had not Hitler taken the initiative four days after Pearl Harbor. Even with the worst of intentions, Germany had neither the resources nor the ambitions to take over the Americas. The German threat to Atlantic shipping was largely gone by 1943, while "Operation Sea Lion," the invasion of England, was also gone by 1942. The English coast was 26 miles from Nazi air bases; the U.S. coast was 3,000 miles!
Good luck Luftwaffe.
In the Cold War, the Soviet Union, certainly, had the means to obliterate the American homeland, thousands of times over. So did the U.S., vice versa, leading to the horrible acronym, Mutual Secured Destruction, "MAD." Combined, both sides had approximately 100,000 nuclear bombs, most at least 100 times more lethal than the two actually used against Japan. It is one of the most amazing facts in human history that for such a long time (nearly a half-century) these two "superpowers" possessed such explosive power and never, not once, chose to use them against each other.
Of all the thousands atomic/nuclear weapons ever deployed, by all countries in the world, it remains a singular truth that only the first two were ever launched against a human target. The code-word for the Cold War, "deterrence," meant that the purpose of a weapon was to remain in-place. If it went off, it lost its purpose, i.e. it "failed."
Against this background, what is the "existential" threat currently facing the United States? Is it external or internal?
Typically, the strategic threat, now and before, sees primarily the "enemy within." Since the 2016 election, the chief focus of the Trump Administration has been to build a wall on the Mexican border so as to "safeguard" the culture inside. Often, the "caravans" coming in, especially illegals, are defined as an "invasion." This stretches the term but acknowledges the origins of the problem, i.e., Central American governments and people.
The American government and people have done nothing to solicit this immigration except to offer a safe haven. Many in the U.S. actually welcome the influx, and over 75 cities offer "sanctuaries" in defiance of federal law.
So, is the issue external or internal, existential or peripheral? It's external since it comes from outside, internal since it shapes the character of the culture. It's existential if it radically alters the internal culture, peripheral if the culture is able to absorb the influx.
Thus, as in earlier immigration waves, the answer hinges on the capacity of the newcomers to "assimilate" within. Thus far, the USA has benefitted from immigration since the focus has been on how they will help the culture, not how the culture will help them.
There are warning signs: illegal entry, scarce documentation, overwhelming numbers, crime, poverty, disease, and violence, plus allegiances to hostile legal or political systems. Historically, the existence of Ellis Island served to safeguard the country from the vices above and still serves as a symbol representing a "nation of immigrants" (President Kennedy's book title).
Now, as before, Americans still are afraid of how foreigners might shape their internal lives. Russia, once an existential nuclear threat, has been reduced to a computer hacker allegedly defining the outcome of local elections. "Cyber," a technology, is distant and complex, however lethal it may yet be. But the cyber threat also comes from outside. China remains the subject most mentioned as external, but few Americans, including the Trump Administration, see it as much more than a trade rival. North Korea has occupied most of public attention, but how existential can "rocket man" be?
Globalization has many consequences. Historically, threats were relatively easy to define. Nationalism was healthy, the Redcoats were from England, Teddy Roosevelt carried a "big stick," the Kaiser and Hitler were from Germany, Mussolini from Italy, Tojo from Japan and immigration was carefully controlled. Now, everything is interconnected, and one can scarcely tell friend from foe. Nationalism is now "white supremacy." History was horrible and needs to be erased. Immigration controls are "racist."
After the defeat at Yorktown, 1781, the British band played "The World Turned Upside Down." Now we know why.