As we prepare for the final presidential debate of 2016, with its inevitable clashes over Donald Trump’s alleged groping of women and the latest WikiLeaks revelations involving Hillary Clinton, let’s pretend for a moment that we are in an alternate universe where the American people are choosing a commander in chief who may have to lead our nation through an unprecedented — and unanticipated — national-security crisis.

It has happened before. In 1988, no one asked either Michael Dukakis or George H.W. Bush about Iraq during the presidential debates — yet soon the United States was called on to repel Iraq’s invasion of Kuwait in the 1991 Persian Gulf War. Similarly, in 2000 no one asked George W. Bush or Al Gore about the threat from al-Qaeda during the presidential debates — yet less than a year later, al-Qaeda had attacked the U.S. homeland and the war on terrorism dominated Bush’s presidency.

Knowing this history, I asked a number of leading national-security experts what question they would ask the candidates — a question that no one is asking today but that could come to dominate the next president’s term in office. Their answers are fascinating — and terrifying.

Several pointed to Pakistan as the epicenter of the next major international crisis. “Pakistan is making nuclear weapons faster than any other country on earth as its society becomes more violent, more radicalized, and more anti-American,” said former CIA and National Security Agency director Michael Hayden, adding “what happens if Pakistan fractures?” Former undersecretary of defense for policy Eric Edelman points out that Pakistan has adopted “a nuclear doctrine that, like Russia’s, foresees the battlefield use of low-yield, short range nuclear weapons” and that “a nuclear confrontation or nuclear war between India and Pakistan . . . would be the most likely route to terrorists getting hold of a functioning nuclear weapon.” What would either major-party candidate do to prevent this?

Others point to the vulnerability of our critical infrastructure. Retired Gen. David Petraeus, former CIA director, points out that “a sustained cyber-attack on our physical and/or virtual infrastructure . . . could prove especially challenging because of the extensive damage it would do, because there is no agreed concept for America’s response, and because it would likely be difficult to achieve unity in determining the appropriate international response.” How would the candidates handle such an attack? My American Enterprise Institute colleague Mackenzie Eaglen suggests an infrastructure attack could come not from cyberspace, but outer space. “China, Russia, and others . . . are developing and testing missiles and spacecraft to destroy or manipulate our satellite constellations, which allow for financial markets to trade in milliseconds, enable our cars and phones to help us get from point A to point B, and undergird the entirety of the US military,” she said. “How will each of you deter or fight back against a Russian or Chinese day-one space salvo?”

Others suggest that the next crisis could involve East Asia. “How would you respond if there were a collision between Japanese and Chinese military forces in the East China Sea — a disputed area that the two countries patrol in close proximity?” asked former CIA deputy director and acting director John McLaughlin. “If some sort of military action ensued, Japan, as a U.S. treaty ally, could call on the U.S. for help in combating China. What would you do?” And how about this for a terrifying question: “What if a North Korean ballistic missile test goes wrong, and a missile lands in Seoul or Tokyo?” asks Michael Auslin, AEI’s director of Japan studies. Wow.

With missiles having being fired at a U.S. warship off the coast of Yemen, reportedly from territory controlled by Iran-backed rebels, several experts raised frightening scenarios involving Tehran. Former CIA chief legal officer John Rizzo asked what the candidates would do if the Iranian government decides “to immediately test the new president and the resolve of Washington in its commitment to the nuclear deal” by taking “a provocative, high-profile act against the US government in the region, such as the kidnapping of diplomats or American servicemen.” Former House Intelligence Committee chairman Peter Hoekstra pointed out that “with the infusion of massive new funds from the Obama administration’s nuclear deal, Iran will have the means to establish forward operating bases for its intelligence and terror front groups in countries in the United States’ southern backyard.” What, he asks, will the candidates will do to address “the very real potential for subversive infiltration by Iranian-linked nefarious operators?”

Then there is Russia. McLaughlin asked, “What would you do if Vladimir Putin used a version of his Crimea or Ukraine tactics in a NATO country that has a large Russian-speaking population, such as Estonia or Latvia? Imagine that he stops short of moving in Russian forces but manages to foment unrest among that population by covert tactics, creating a measure of protest and instability. And imagine that this leads the affected country to invoke Article 5 of the NATO Treaty, which calls on other NATO countries to come to the defense of the member under threat. How would you handle this?”

The questions — and potential crises — are endless. What if Saudi Arabia collapses, plunging the Persian Gulf region into chaos? Thanks to President Obama’s defense cuts, the U.S. military now has the resources to handle just one major contingency at a time, so what if we face two? The Islamic State recently attacked a U.S. base in northern Iraq with a chemical agent— what if the terrorist group carried out a chemical or biological attack in Europe or the United States?

There is no evidence that either presidential candidate has answers to these questions. Trump is an isolationist who wants to withdraw from the world to focus on building bridges and roads. And Clinton is a corrupt politician whose main achievement as secretary of state was blowing the Russian “reset” and paving the way for the disastrous Iran deal while possibly selling special State Department access to Clinton Foundation donors.

With three weeks to go before voters choose the next commander in chief, we’ve yet to have a serious foreign-policy debate. We now return you to the reality show that has become our presidential election.

At an event held by Retired American Warriors PAC Oct. 3, Republican presidential candidate Donald Trump offered his plans for protecting the United States against cyber attacks and slammed rival Hillary Clinton for her handling of her emails as secretary of state. (The Washington Post)

Read more from Marc Thiessen’s archive, follow him on Twitter or subscribe to his updates on Facebook.