Rick Hampson

USA TODAY

Ever since the second one ended in explosions bright as the sun, we have feared the start of the third. World War III would be the real war to end all wars, and maybe the human race. Einstein said he didn’t know with what weapons it would be fought, but that World War IV would be settled with sticks and stones.

Now, America is butting heads in Syria with Russia, the other great nuclear power. We are watching the range of North Korean nuclear missiles stretch inexorably toward Seattle. And people again are thinking about the unthinkable: an attack of which there is no warning, for which there is no defense, and from which there is no escape.

At 92, Annamarie Choo has lived through it all — Hiroshima and Nagasaki, the Berlin Wall, the Cuban Missile Crisis. Now, she says, “In the top of my mind, I think about war. I don’t know how to say this, other than Russia and America, there are communication problems, a big gap. They don’t really understand each other.’’

She lives in a retirement community on a mountain in western North Carolina, and voted for Hillary Clinton. In Malta, Ohio, a 45-year-old auto parts store manager who voted for Donald Trump feels likewise.

“My greatest fear, I think, is a third world war,’’ says Jeremie Clifford. “We’re letting the leader of North Korea get away with more, or just as much as, what we let Saddam Hussein get away with.’’

Visit Curtis Ingram’s barbershop in Mauldin, S.C., and you’ll hear more of the same: “I believe we’ll wind up in another war,’’ he says.

“World War III’’ surged as a Google search term last month. Trump had ordered a missile attack on a Syrian airbase to retaliate for Syria’s use of chemical weapons on civilians. Tensions with North Korea had ratcheted up over that nation’s rocket tests; the U.S. said it would dispatch an aircraft carrier, and North Korea said it could sink such a ship. According to a Public Policy Polling survey taken last month, 39% of all voters (and two thirds of Clinton voters) think Trump will get the U.S. into World War III during his presidency.

It’s hard to know how hard to worry. This week, Trump said he’d be honored to meet North Korean leader Kim Jong Un — only with certain preconditions, the White House hastened to add — and had a phone call with Russian President Vladimir Putin.

But last week Trump said a "major, major conflict" with North Korea was possible. Asked on CBS’ Face the Nation whether the U.S. might use force to stop North Korea’s program, he said only, "We’ll see.’’

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The Doomsday Clock, created in 1947 by the Bulletin of the Atomic Scientists to reflect the proximity of nuclear war, is almost as close as it’s ever been to midnight, or Doomsday. Earlier this year the clock (which actually hangs on the wall in the journal’s Chicago office) was moved 30 seconds forward, to two and a half minutes before midnight. That’s the nearest it’s been to Doomsday since 1953, after the U.S. and the Soviet Union both tested their first hydrogen bombs.

David Wood, pastor of The United Church of Lincoln, Vt., was 5 when the clock debuted at seven minutes before midnight. Now, he says he’s scared that Trump, who strikes him as “impetuous,’’ has control of the nation’s nuclear codes.

He says the old worries about nuclear war have been revived “because of the fear that is being fostered today, not just in our country, but in other countries as well. Nationalism, this sense of fear, makes us more trigger-happy.’’

A different opinion is offered by Ed O'Connell, 48, a contractor who lives in Allendale, N.J.: “We’ve got to make sure that anyone who threatens us, they’ve got to think twice.’’ He says this means what Trump has proposed — “increasing our national security with putting more money into the military.’’ He’s among the 40% of voters who don’t think World War III is inevitable in the next four years.

Fears of World War III were raised in the last presidential campaign — by Trump. In a speech in Orlando six days before the election, Trump accused Clinton of "wanting to start a shooting war in Syria, a conflict with a nuclear-armed Russia that could very well lead to World War III.’’

The actual proximity of World War III is hard to gauge. War between great powers need not be nuclear, and even nuclear exchanges need not escalate into world war.

Regardless, no one should confuse current nuclear tensions with those of the high Cold War, when the nation and the Soviet Union had roughly equivalent nuclear arsenals; diametrically opposed political ideologies; and (in different ways) dreams of world domination.

It was a jittery time. Roughly half of Americans regularly told pollsters they expected to die in a nuclear war. In the atmosphere, nuclear powers test exploded H-bombs like warning shots. At home, American families built fallout shelters.

That included the Andersons of 3204 Woodrow Avenue in Fort Wayne, Ind., an industrial city that was considered a prime target in case of Soviet attack. “Everyone knew we’d get it,’’ one Fort Wayne resident, Vera Howey, told USA TODAY years later. “I worried about that.’’

In 1968, Howey bought the Anderson home, including the double-hulled steel fallout shelter buried in the front yard. When the Cold War ended, it was an unnecessary reminder of stressful times. She donated it to the Smithsonian.

In 1998, when India-Pakistan tensions raised fears of a regional nuclear war, she confessed to still being “a worry wart. … What if Pakistan gives the bomb to Iran?’’

Vera Howey died in 2003 at 73. Her worries were over.

While she suspected there was nothing worse than nuclear war — “The living will envy the dead,’’ as the saying had it — she also knew, from experience, that fear of it is bad enough.