For now, as the primary shifts from the overwhelmingly white states of Iowa and New Hampshire to the more diverse states of Nevada and South Carolina, it is a source of weakness. Both moderates are running in single digits nationally in support among people of color, with Klobuchar barely registering in recent polls. And in Nevada, the first state with a significant non-white voting population, they each have 10 percent support — tied for fifth, according to The Nevada Poll.

Asked about Buttigieg and Klobuchar following a Monday event with one of their competitors, Elizabeth Warren, Héctor Sánchez Barba, executive director of Mi Familia Vota, declined to address the candidates specifically. But he said, “A lot of these campaigns have never engaged with the Latino community. So, I’m not speaking about which one does or doesn’t, but for us, it’s important to see their past, their present and their commitment for the future, because we know this game: They come every four years and make all kinds of promises, and then they forget about our community until the next election.”

He called Klobuchar’s inability to name Mexico’s president, Andrés Manuel López Obrador, “unacceptable” and “embarrassing.”

Here's the end:

GV: just one final question. How do you plan to win the support of the Hispanic vote in NV and the whole southwest if you can't tell me who the president of Mexico is?.....

AK: Because my heart is with the people of this country and my heart is with immigrants... pic.twitter.com/HQJr9wzd6J — Alex Thompson (@AlxThomp) February 15, 2020

Iowa state Rep. Ross Wilburn, a Klobuchar surrogate who spoke at the legislative caucus brunch, characterized Klobuchar’s blunder as a “small gaffe,” adding, “I’m sure that she knows President Obrador’s name now, as well as Prime Minister Trudeau and Angela Merkel and on down the line.”

He said, “What’s more important is the policies that she will put in place as president respecting our international partners, respecting our allies, as opposed to what the current president is doing.”

But Klobuchar’s lapse was still resonating throughout the campaign days after she committed it — a running joke and a source of bewilderment in Democratic circles here.

Buttigieg, who did know Obrador’s name, used the opportunity to needle Klobuchar about it at a rally on Sunday.

“I guess what it says is that there is more to being prepared than how many years you’ve spent in Washington,” he said.

Nevada is notoriously difficult to poll, with its high transitory population, shift-work and relatively short history of caucusing. Many people, said Aaron Ford, the state’s attorney general, are still making up their minds.

For Buttigieg and Klobuchar — as well as Warren, who is also struggling with people of color — it is almost imperative that the electorate break late. They are counting on momentum from their performances in Iowa and New Hampshire to turn caucus-goers toward them here — and to propel them in South Carolina and on Super Tuesday.