The one-year anniversary of the suspension of normal life because of the coronavirus pandemic offers a reminder of how naive we were in mid-March 2020.

When baseball spring training and Broadway theaters shut down on March 12, there were only about 1,300 reported cases of COVID-19 in the United States. That’s why the closures were envisioned as temporary, with the start of the major league season delayed by two weeks and Broadway slated to go dark for a month.

How little we knew then — and how little at the time we were able to emotionally accept. 

Now, looking back, the past year has provided enduring lessons about how the nation reacts to unimaginable tragedy. Here are some of them that go beyond the most obvious lesson of them all: Don’t have Donald Trump as president in a crisis. 

America, when it sets its mind to it, remains an awe-inspiring nation

A year ago, there was widespread scientific skepticism that a vaccine could be developed within 18 months. And I have yet to find the seer who predicted that in March 2021 we would be working with three highly effective vaccines and be coming close to inoculating 3 million Americans per day. 

As Andy Slavitt, a key Biden administration health figure, said at a Monday briefing, “We’re at a pace seen nowhere else around the world.”

The era of budgetary restraint may be permanently over 

For many conservatives, the two biggest news stories of the past week involved Dr. Seuss and Oprah’s interview with the Runaway Royals. 

In contrast, the united opposition of Senate Republicans to Joe Biden’s $1.9 trillion pandemic package inspired barely a flicker of passion on the right. Unless there is tangible evidence of a major upsurge in inflation — beyond vaporous warnings from nervous economists — we have entered an era when deficits truly don’t matter. 

Anything — even a small protective piece of cloth — can be politicized

When the histories of the pandemic are written, the virulence of the anti-masking frenzy will seem baffling. Yes, there were anti-mask protests during the influenza epidemic after World War I. But a century of scientific progress has not tamed such know-nothing sentiments. 

It is simple to understand the basics — the virus is transmitted by airborne particles and wearing a mask stops many of them. Even for mask skeptics, common courtesy should have prompted compliance with pandemic fashion. Instead, sadly, flamboyantly shunning masks has become a self-destructive way to stick it to the liberals.

The failures of public health messaging can be lasting 

Yes, the science of COVID-19 has been dramatically evolving and many things that were commonly believed a year ago proved to be wrong. But in 2020, the government and many authority figures, including the press, were slow to correct initial errors.

In particular, mask wearing was discouraged in March 2020, partly out of fear that consumers would snap up vital medical protective equipment. As a result, the dramatic, but ill-explained, turnabout in public health messaging about masks fed countless conspiracy theories. 

The original fear was that COVID-19 was spread by virus residues lingering on surfaces. Thus began the era of washing down grocery bags with Lysol and recoiling in horror from elevator buttons. 

But as the science changed, the government has been slow to sound the all-clear about surfaces. So what we now have is what Zeynep Tufekci, writing in The Atlantic, calls “hygiene theater.” 

Marriott, for example, advertises that all its hotel rooms are “thoroughly cleaned with hospital-grade disinfectants.” Far more effective against COVID-19 would have been to spend the same money on better ventilation within hotels. 

The moral superiority of liberals about COVID-19 can be self-defeating

This is a hard one for me to write because I too have often been guilty. 

But, in hindsight, it seems a tad embarrassing to recall the rage against Florida Gov. Ron DeSantis for not closing the state’s beaches during spring break last March. We now know that outdoor transmission of the virus is rare. 

None of this is designed to excuse the super-spreader policies of South Dakota Gov. Kristi Noem who encouraged the mask-less Sturgis Motorcycle Rally and its accompanying indoor drinking at the height of the pandemic. Or the recent decision by Texas Gov. Greg Abbott to prematurely lift all mask requirements in the state solely as a boost to business. 

But sometimes liberals (like me) are tempted to bask in self-righteousness rather than to figure out ways to convince our fellow citizens to do the right thing. 

The nation needed the biggest ad campaign since World War II or, at least, the cigarette wars

Where was the Don Draper of the pandemic? Most public service ads about masks, for example, had the urgency of anti-littering commercials. And without public education, the myth spread that COVID-19 was little more than a bad case of the flu for those under 50. 

In truth, we are now learning how devastating the long-haul version of the disease can be for adults who were never at risk of dying or facing a lengthy hospital stay. A leftover political slogan might have been effective in curbing risky behavior among young adults: “It’s your fight, too.” 

Never take Andrew Cuomo as a role model.

The New York governor’s hastily completed book, “American Crisis: Leadership Lessons from the COVID-19 Pandemic,” should be brandished whenever a political leader tries to take a premature victory lap. What makes the cautionary tale even more jarring is that Cuomo lied about nursing home deaths in the book as well as in public documents.

But all these errors and misjudgments should not take away from the glee that today’s America seems on target to beat the pandemic through mass vaccination.

Walter Shapiro has covered the last 11 presidential campaigns. He is also a fellow at the Brennan Center for Justice at NYU and a lecturer in political science at Yale. Follow him on Twitter @MrWalterShapiro.