Chief of Staff of the Army Gen. Mark Milley, left,...

Chief of Staff of the Army Gen. Mark Milley, left, and Defense Secretary James Mattis, speak before President Donald Trump bestows the Medal of Honor on retired Army medic James McCloughan at a White House ceremony on July 31. Credit: Jabin Botsford

In 1964, as Moscow and Washington were locked in a nuclear competition, the satirical blockbuster “Dr. Strangelove” mesmerized the nation. It portrayed an unhinged general who triggers a nuclear first strike against the Soviets behind the president’s back.

As Secretary of Defense James Mattis (along with the Joint Chiefs chairman, Gen. Joseph Dunford) met with reporters on the White House lawn this week, after North Korea’s sixth and most powerful nuclear test, it seemed as if the premise of “Dr. Strangelove” premise had been reversed.

The retired general was a voice of reason at a time when President Trump pumps out incendiary Korea tweets without consulting military or civilian advisers. We’ve come to depend on Trump’s generals to temper the erratic impulses of our civilian president - and to prevent the crisis over North Korean nukes from escalating into an unintended war.

The generals know there are no good options in dealing with that country’s nuclear challenge. Over the last three decades, both Republican and Democratic administrations have tried carrots and sticks to roll back Pyongyang’s nuclear program, which is now estimated to have produced 60 weapons.

Neither threats nor sanctions nor cyber-attacks have stopped Pyongyang’s program, let alone reversed it. Nor have negotiations had any lasting success, even after the last Bush administration agreed to recognize the North Korean state if it gave up its nukes.

At this point, North Korean leader Kim Jong Un appears set on keeping his weapons program so as to preclude the fate of Iraq’s Saddam Hussein or Libya’s Moammar Gadhafi. He’s made clear that talks won’t change that. This is the reality that Trump’s generals recognize.

Of course, Kim has upped the ante with his threats to target the U.S. mainland or territories. These threats are bombast, since the young leader is not suicidal.

But his hyperbole, matched by an impatient Trump, who wants a quick “win,” could lead to consequences neither side wants.

What Mattis also recognizes is that the costs of military action are too high, unless such action is required to prevent an attack on the United States.

A preventive strike to eliminate North Korea’s weapons wouldn’t wholly succeed since many are buried deep underground in secret locations. North Korea would likely respond with a conventional missile attack on South Korea, which could quickly destroy the capital, Seoul, killing tens of thousands of civilians as well as thousands of U.S. troops based in the country.

Thus Trump’s twitter pledge last month, made from his New Jersey golf club, to rain “fire and fury like the world has never seen” on North Korea if it made “any more threats to the United States” set impossible red lines. Indeed, Kim has already made more verbal threats.

Mattis, on the other hand, laid down much more cogent markers. “We have the ability to defend ourselves and our allies - South Korea and Japan - from any attack,” the defense secretary said. He added: “Any threat to the United States, or its territories - including Guam - or our allies will be met with a massive military response.”

What Mattis appeared to be indicating was that a threatened North Korean military - not verbal - attack would unleash a U.S. military response. However, generals can advise but not set policy. Policy requires a political decision by the president in consultation with civilian and military advisers - and with our key Asian allies, South Korea and Japan.

Yet right now, there appears to be no coherent policy process in place in the White House. The new chief of staff, retired Gen. John Kelly, is trying to institute some policy discipline. But he and the national security adviser, Gen. H.R. McMaster, are still undercut by Trump’s temper - and his tweets.

Meantime, on the diplomatic front, there is a stunning vacuum. Secretary of State Rex Tillerson has said nothing on North Korea for weeks. The post of ambassador to South Korea is vacant, and there is only an acting assistant secretary for East Asia at the State Department. This makes it all the harder to implement harsher sanctions against Pyongyang, which is worth trying despite past disappointing results.

Moreover, the president has tweeted insults at the new president of South Korea and threatened to start a trade war with Seoul at a time when the U.S. should be standing shoulder to shoulder with South Korea against Kim’s threats. And Trump’s incoherent twitter stream toward China - one day praise, another day threatening to cut off all trade - only undercuts any chance of persuading Beijing to be tougher on its dangerous neighbor.

So while Mattis’ appearance on the White House lawn gave an inkling of what a presidential presence might look like, it also reminded us of how topsy-turvy foreign policy has become in the Trump presidency - and how the nuclear standoff with North Korea could escalate.

Trudy Rubin is a columnist for the Philadelphia Inquirer.

Newsday LogoYour Island. Your Community. Your News.Digital AccessOnly 25¢for 5 months