After the Great Pandemic has passed and we emerge from Great Depression II, what will be America's mission in the world?
What will be America's cause?
We have been at such a turning point before.
After World War II, Americans wanted to come home. But we put aside our nation-building to face the challenge of a malevolent Stalinist empire dominant from the Elbe river to the Barents Sea.
And after persevering for four decades, we prevailed.
What, then, did we do with our epochal victory?
We alienated Russia by moving our NATO military alliance into the Baltic and Black Seas. We launched bloody, costly crusades for democracy in the Middle East that, invariably, failed. We exported a huge slice of our manufacturing capacity and economic independence to a coddled China.
Historically, blunders of such magnitude have undone great powers.
Even before COVID-19, Americans had begun to realize the folly of decades of mindless interventionism over matters irrelevant to our vital interests. "Unsustainable" was the word commonly associated with our foreign policy.
But if our foreign policy was unsustainable during President Trump's economic boom, with unemployment at record lows and a bull market to rival the Roaring '20s, can an interventionist foreign policy be sustained after the losses of this major depression we have induced to kill the pandemic?
If the Democrats win in November, we know their priorities: national health insurance, carbon taxes, the Green New Deal, open borders, amnesty, reparations and wealth redistribution to reduce social and economic inequality -- an agenda costing trillions of dollars.
And Democrats will be looking at the defense budget as a slush fund to finance this new progressive era.
If the Republicans win, given the influence of hawks and neocons among the party elite, interventionism may get another run in the yard.
Having been exposed as naive beyond belief for their indulgence of China from the Bush I days to 2016, some Republicans are looking to make amends by casting China in the Soviet role in Cold War II.
There is talk on Capitol Hill of refusing to pay off U.S. bonds that Beijing holds and of suing China for the damages done by the coronavirus, as China failed to alert the world the pathogen was loose.
Americans should think long and hard before defaulting on U.S. government debt and consider the consequences if we open a door to claims against sovereign nations for past sins.
Iraq was invaded in 2003 to force it to give up illicit weapons of mass destruction it did not have. Baghdad could have a case in international court against America for the unprovoked war waged against that country.
While the U.S. appears determined to bring back manufacturing -- especially of products critical to the health, safety and defense of our nation -- there seems to be no stomach among the public for a war with China.
But again, with the democracy crusades now repudiated, what is America's cause, what is America's mission in the world?
Preventing climate change, say our liberal elites. Yet, even before the pandemic, global warming ranked near the bottom of national concerns.
The situation in which America will find herself after the virus passes and depression lifts will be almost unprecedented.
We will have the same treaty obligations to go to war on behalf of dozens of nations in Europe and Asia and at the same time, we will be running deficits on the order of $3 trillion a year with a shrunken economic base.
If Trump wins, borders will be tightened. The U.S. withdrawal from the Mideast will continue. U.S. manufacturing will begin to be repatriated. Transnational institutions will be downgraded, ignored and superseded.
The watchword will be what it has lately been: "America First."
In a second Trump presidency, there would likely be even less concern for how other nations rule themselves.
Does it matter to us if Russia is led by an autocrat not unlike a Romanov czar, that Hindu nationalism wields the whip hand in India or that Hungarians have rejected Earl Warren's ideas about liberal democracy?
In recent decades, the U.N. General Assembly has seemed to resemble the bar scene in "Star Wars." But is how other nations choose to rule themselves any business of ours, if those nations do not threaten us?
In the 19th century, when the Hungarians had risen up against the Hapsburg Empire and sought U.S. intervention, Henry Clay opposed it:
"Far better is it for ourselves ... and for the cause of liberty ... that we should keep our lamp burning brightly on this western shore, as a light to all nations, than to hazard its utter extinction amid the ruins of falling or fallen republics in Europe."
Not only President Trump's preferences but also events seem to be driving us toward such a destiny.
To borrow from the title of historian Walter A. McDougall's classic work, America's future is as a promised land, not a crusader state.
Patrick J. Buchanan is the author of "Nixon's White House Wars: The Battles That Made and Broke a President and Divided America Forever."