On July 20, 1969, Americans landed on a relatively placid place on the lunar surface called the Sea of Tranquility.

Fifty years hence, a sea of tranquility has not landed on Americans.

Indeed, rather than rallying around the remembrance of a future-focused country sending Apollo 11 astronaut Neil Armstrong to make a "giant leap for mankind," a too-often unkind man and some of his followers took a step back into the nation's nativist past.

The contrast between the two eras is stark. But not because there wasn't strife 50 years ago.

In fact, instead of letting the social and political upheaval of the '60s eclipse its moon mission, America overcame it.

The year that NASA's program culminated in Apollo 11's monumental moment saw the second-highest levels of U.S. troops in Vietnam. A year earlier, the tragic assassinations of Martin Luther King and Robert F. Kennedy and the chaotic Chicago Democratic convention shocked the conscience of a country already reeling from racial tension.

So although unifying a fractured U.S. wasn't its original intent, the Apollo program provided a more positive construct for the country.

And at least when it came to the space program, that era's presidents — from JFK, whose "New Frontier" went beyond a campaign slogan, to LBJ, who continued Kennedy's commitment to the moonshot, to even a newly elected Richard Nixon — were all relatively visionary leaders.

Each used the bully pulpit not to bully fellow Americans but to rally them to a great national cause — even after the U.S. fell behind the U.S.S.R., which launched Sputnik and Yuri Gagarin, the first man in space.

Rather than concede the space race after these Soviet achievements, the U.S. got to work at government's highest levels, in higher education, and even in high schools stressing science, math and engineering education. And there were efforts from several sectors in-between, including those that also eventually launched innovation in industries well beyond Mission Control in Houston and Cape Kennedy in Florida — places like Silicon Valley.

President Donald Trump has been inconsistent in considering America's role in space, alternately calling for (but not really following up on) a return to the moon, a mission to Mars, and the establishment of a U.S. Space Force.

All these may have merit (money is a different issue). But terrestrial moonshots also could unite the U.S. the same way the space race did.

Curing cancer, for one.

Or, as this incendiary week suggests a need for, eradicating the cancer of racial strife, which 50 years after Apollo is still a Deimos-like dread deadening our country's cohesion.

Other worthy endeavors could include elevating education to once again graduate the world's best-performing students. Or an all-out effort to treat addiction as the health and social crisis that it is.

Or, in a challenge that would summon the technological, political, social, and even spiritual leadership that landed a man on the moon, preserving mankind here on earth by leading an effective response to the climate crisis.

Just as the moon has intrigued and inspired through the ages, perhaps the lunar landing anniversary can inspire a new generation of Americans to preserve the Earth it orbits.

Indeed, the moon can give new perspective — and appreciation — of our planet, just as it did for Apollo 11 astronaut Michael Collins, who told the PBS NewsHour this week that, "The moon was nothing compared to my view of home planet.

"It was it. It was the main chance. I would look out the window, and there would be a tiny little thing. You know, you could obscure it with your thumb. But every time you put it away somewhere else, it would pop out. It wanted you to look at it. It wanted to be seen. It was gorgeous. It was tiny, shiny, the blue of the oceans, the white of the clouds, little streak of rust color that we call continents. It just glowed.

"Having gone out 240,000 miles and seeing it gives me a much greater sense of fragility, a much greater urge to do something to protect that fragility as we go along."

Americans are an extraordinary people.

And when we rise to our better angels — and especially when we have seminal achievements like rising to the lunar surface — we can truly be an exceptional nation.

Let's return there.

Even if we stay right here.

John Rash is a Star Tribune editorial writer and columnist. The Rash Report can be heard at 8:20 a.m. Fridays on WCCO Radio, 830-AM. On Twitter: @rashreport.