In 2008, then-U.S. Sen. Barack Obama understood the importance of symbolism. Among the carefully choreographed campaign appearances in his historic run for the White House was a speech in Berlin. Against the backdrop of a crowd estimated at 200,000, Obama presented himself as an internationalist who would unify a frayed Atlantic alliance.

On Sunday, a much larger crowd than the one that greeted Obama in Berlin — in fact the largest since liberation from Nazi occupation — marched in Paris as a show of unity in the face of terrorism. Among the more than 1 million marchers were 44 world leaders who linked arms in solidarity.

Neither Obama, nor Vice President Joe Biden, nor Secretary of State John Kerry was among them. The only Cabinet-level official present was Attorney General Eric Holder, who met with French President Francois Hollande. But instead of attending the march, Holder appeared on four Sunday morning talk shows.

The administration's no-show — only U.S. Ambassador Jane Hartley, an Obama campaign contributor and political appointee attended the Paris march — was an embarrassment for the United States.

The march would have been an ideal international opportunity to show solidarity with America's oldest ally, France, and to reassert that terrorism is a global scourge that can be defeated only by an integrated international effort.

To be sure, both the Bush and Obama administrations have been at the vanguard of this global effort, and the United States has coordinated intelligence and other efforts with numerous allies, including France. Obama also has worked to internationalize military efforts against the Islamic State of Syria and the Levant (ISIL), as well as other campaigns against violent extremists.

But symbolism matters, as the president surely knows. In fact, he acknowledged the importance of solidarity in the wake of last week's attack when he said, "I want the people of France to know that the United States stands with you today, stands with you tomorrow."

Stand, maybe. But march? Obama couldn't be bothered.

According to the White House, Obama had no events on his schedule on Sunday, yet he also skipped a Washington march just blocks away from the White House. Biden was home in Delaware with no public events.

It may have been an inconvenience for Obama to attend. But he sure seems motivated to alter his schedule for fundraisers or golf. And, yes, no doubt security was a concern. But it's a concern for other world leaders, too, including Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas, who both stood, and marched, with the people of France on Sunday.

Kerry, who is fluent in French and well-versed in diplomatic symbolism, would have been a minimally appropriate U.S. representative. But the dogged diplomat was working as usual, attending an event in India, another key ally.

Ideally Kerry could have convinced Indian Prime Minister Narendra Modi to attend the Paris rally with him. India has also faced devastating terrorism, including a particularly deadly 2008 assault that killed scores in Mumbai.

Responding to criticism of the administration, Kerry said: "I really think that this is sort of quibbling a bit."

Kerry's wrong. The administration's snub was noted across the Atlantic — and even some former diplomats who served in Democratic administrations criticized the administration.

And by mid-Monday, even the White House had waved the white flag. "I think it's fair to say we should have sent someone with a higher profile," said White House press secretary Josh Earnest.

The fact that apparently neither Obama nor his senior advisers perceived the international importance of the event is yet another unforced error from an administration that should know better after six years.

As for the march itself, France should be proud of how its citizens have rallied to remember the slain 17 innocents and vowed to uphold values essential to a civilized democracy, including a free press and a continued commitment to pluralism.

Indeed, among the ubiquitous "Je suis Charlie" placards were some saying "Je suis Ahmed," honoring police officer Ahmed Merabet, the son of Algerian immigrants who was killed defending the satirical newspaper Charlie Hebdo.

The sea of citizens supporting these ideals was highlighted, but not eclipsed, by the world leaders linking arms. It's too bad that Obama, whose administration has been criticized for a "lead from behind" foreign policy, wasn't arm-in-arm with them.