When CBS News brought Dwight Eisenhower back to Normandy for the 20th anniversary of the D-Day landings in 1964, you might have expected the former commander of Allied forces to conclude with a triumphal comment. Instead, CBS captured an anguished Eisenhower against the backdrop of crosses at the U.S. cemetery at St. Laurent, ruminating: “We must find some way . . . to gain an eternal peace for this world.”

The 70th anniversary of D-Day this week offers a moment to reflect on U.S. strength and weakness, and the way we sometimes confuse the two. Eisenhower was perhaps our greatest modern military commander. But he was a cautious and sometimes conflicted man, without any of the bluster of a George Patton or Douglas MacArthur. His gift was coordinating the talents of sometimes petulant subordinates — and persevering through the almost ceaseless U.S. military blunders on the way to the Normandy landings.

Perhaps it’s a consequence of the United States being a relatively young nation that had to tame a wild frontier, but through our modern history, Americans have had a tendency to worry about whether our leaders are “tough enough” for the world’s challenges. Presidents who talk about their yearning for peace, as Eisenhower often did, are frequently pummeled by commentators for being too “soft.”

We’ve recently been in one of those cycles of national worry, as critics attack President Obama’s supposedly feckless and weak-willed foreign policy. The particulars of the case against Obama involve his reluctance to use military force after the frustrating wars in Iraq and Afghanistan. The Economist magazine raised the basic question of Obama’s credibility, asking in a May 3 cover headline: “What would America fight for?”

I agree that Obama’s foreign policy has not been as firm, especially in dealing with Syria and Russia, as it should have been. As a result, the United States has suffered some reputational damage. But listening to the recent debate, I have increasingly been struck by its recurring cyclical themes, as opposed to the specifics involving Obama. Yes, this president may be overly cautious. But a retreat to lick the nation’s wounds is fairly common after wars — and rarely does lasting damage.

A useful compendium of anxiety about U.S. weakness is a book called “Taking on the World,” about columnists Joseph and Stewart Alsop, written by Robert W. Merry. He explains that at nearly every point from the late 1930s to the late 1960s, the Alsops (especially Joe, the dominant voice) were warning that weak and irresolute U.S. leaders would open the door for our adversaries — in Europe, China, Korea and Vietnam. Sometimes the Alsops’ jeremiads proved correct. But often, they were flat wrong.

The Alsops’ suspicion of Eisenhower was especially sharp. They feared Eisenhower’s willingness to make peace in Korea would open the way for Russian and Chinese aggression. “The future of Asia may well be at stake” in maintaining French power in Vietnam, Joe wrote in 1954. Similarly, wrote Stewart in 1955, the French retreat from Algeria “could fatally weaken the Western alliance.” The Atlantic alliance would “founder” if the British were defeated over Suez in 1956, wrote Joe. U.S. defenses would be gutted if Eisenhower cut $5 billion from the $40 billion defense budget in 1955. And on it went.

The Alsops’ concern about Eisenhower reached its apogee during the debate over a supposed “missile gap” between Soviet and U.S. strategic forces. In a 1958 column, Joe accused Eisenhower of being “misinformed” or “consciously misleading the nation” about the “flaccid” U.S. shortfall. Joe even pushed then-Sen. John F. Kennedy to make a 1958 speech about the “peril” represented by this imagined gap.

Ike knew from intelligence that the gap was nonexistent, but he feared blowing his sources, so he let the worriers rant on. When Kennedy became president, his secretary of defense, Robert McNamara, finally seeing the intelligence, announced that the gap was a myth. Joe at first thundered that McNamara had been “hoodwinked by the bureaucracy.”

Then came Vietnam, a war that Joe chronicled and championed — and that he saw as an ultimate test of U.S. willpower. He brooded that Lyndon Johnson would display “presidential weakness” and applauded every escalation that showed Johnson would not “subside by degrees into surrender.” The United States finally retreated from Vietnam, but over time U.S. global power remained greater than ever.

The worriers get one big thing right. A strong, forward-leaning United States is essential for global security. But many of the fulminations about supposed weakness and retreat of U.S. power tend to be mistaken.

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