(CNN) Like his recent predecessors, President Donald Trump sits in the Oval Office at the Resolute Desk. But in battling the coronavirus pandemic , he has been anything but resolute.

Again and again, Trump wobbles under pressure from seesawing stock values and poll numbers, criticism and praise, media scrutiny and phone chats with friends. He embraces the self-flattering moniker of "wartime President," while displaying little of the steadfastness linked to successful crisis leadership.

"He's just so unsteady," observes presidential historian Robert Dallek, whose subjects have included Franklin Roosevelt, John F. Kennedy and Richard Nixon. "He's desperate for praise, for approval. To wear your neuroses on your sleeve the way he does -- it's unprecedented."

Trump wavers even on using the wartime powers he claims. He invoked the Defense Production Act , empowering him to compel private companies to produce health care equipment such as ventilators, but shrank from implementing it after business and free-market ideologues objected.

On Thursday, he insisted governors like Andrew Cuomo of New York didn't need all the ventilators they've pleaded for anyway. On Friday, after White House talks with General Motors on voluntary ventilator production faltered, he conceded the equipment was "much-needed," blasted the company and vowed to use those presidential powers after all.

At his televised briefing, the President asked that governors "be appreciative" of his administration's work. If they aren't, he acknowledged, hurt feelings shape his responses.

"If they don't treat you right, I don't call," Trump said.

A presidential model going back to Lincoln

A vacillating commander in chief turns the model for wartime leadership upside down. In the Civil War, it was Gen. George McClellan, not President Abraham Lincoln, who wavered on taking the fight to Confederate Gen. Robert E. Lee. Lincoln replaced him with someone who would.

One present-day soldier fighting coronavirus applies a World War II analogy to Trump's behavior: backing off social distancing now, while health care professionals struggle with existing cases, would be like withdrawing air cover for D-Day troops moving toward enemy fire at Normandy.

"That's a tough message to swallow for those of us on the front lines," University of Southern California emergency room doctor Ryan McGarry told CNN's Jake Tapper.

In early stages of the threat, Trump downplayed the coronavirus as "under control" for fear of disturbing the solid economy that represented his top re-election asset . When the growing pandemic could no longer be dismissed as a media scare, he shifted and shook up his administration's coronavirus task force.

Since then he has oscillated between embracing or disputing warnings from health advisers, between communicating sunny confidence or sober concern to fretful Americans weighing the challenge ahead. He takes comfort from Wall Street run-ups and scrambles after reversals.

Adopting a newly grave public mien two weeks ago as he declared a national emergency, Trump savored his discovery that "people actually liked it." But last week, having backed tough social distancing guidelines prescribed by health officials, Trump buckled before dire economic forecasts.

"WE CANNOT LET THE CURE BE WORSE THAN THE PROBLEM ITSELF," the President tweeted. He suddenly held out Easter as a target for relaxing restrictions and revving up business and social activity again.

True to form, Trump soon shifted again.

Health officials countered pleas from anxious business leaders with warnings of mounting illness and death, especially among the elderly. Reacting, Trump proclaimed in a tweet that "seniors will be watched over protectively and lovingly" and "my first priority is always the health and safety of the American people."

Lyndon Johnson and George W. Bush reaped little benefit from their war efforts

Trump has benefited from the American impulse to rally around presidents during national crises. The results, for public health and the economy, will determine whether his recent uptick in approval persists

Neither voters nor historians reward every wartime president for perseverance. In 1968, Lyndon Johnson abandoned his re-election after Vietnam War setbacks eroded his public support.

"The difficulty of the task is no excuse for avoiding it," George W. Bush, struggling with the Iraq War, declared in his 2005 inaugural. Bush left office deeply unpopular, the Middle East war discredited by successors Barack Obama and Trump alike and the economic catastrophe of the 2008 financial collapse on his head.

The presidents most revered for wartime leadership displayed unshakeable will to prevail for vital national objectives.

"Let us strive on to finish the work we are in," Lincoln implored near the end of his four-year battle to save the Union. Eight decades later, Franklin Roosevelt repeated those words from "America's greatest wartime president" as he pressed toward victory in the third year of World War II.

Trump, by contrast, shifts attention from his administration's efforts to his ego and election prospects. Lamenting that reporters "really don't like me," he raged last week against news coverage reflecting health officials' calls to stay the course.

"The lamestream media is the dominant force in trying to get me to keep our country closed as long as possible in the hope that it will be detrimental to my election success," the President tweeted. "The real people want to get back to work ASAP."

By Friday, his message flip-flopped again. "The media has really been fair," Trump said.

Approaching a Tuesday decision on social distancing guidelines, Trump defended his talk of getting America back in business by Easter. It might work, he explained, in parts of the country less affected by the coronavirus so far.

"Or maybe we don't do that," the wartime commander hedged. "We also want it to open safe."