Candidates participating in the debates including O’Rourke, Sanders and Warren stopped by the Homestead facility in Florida

For all the unprecedented scale and diversity of the massive number of candidates vying for presidential nomination of the Democratic party, they can be sheeplike in their herd behavior.

No fewer than 12 of the 20 candidates who are appearing at the NBC News debates in Miami this week are making their way to the same spot that has become the current must-do photo op for the presidential hopefuls.

Sanders campaign says he will close migrant detention centers if elected Read more

The setting is an immigration detention center for child migrants in Homestead, 30 miles south of Miami. Here, in a scrubby bit of wasteland, a city of white tents houses up to 3,000 child migrants in conditions that protesters say are far from humane.

And it is here that the Democratic presidential candidates have been landing like bees to the hive. On Monday it was Eric Swalwell, the congressman from California.

On Wednesday, it was Elizabeth Warren and Amy Klobuchar, US senators for Massachusetts and Minnesota, respectively.

On Thursday, New York City’s mayor, Bill de Blasio, snuck in before many of the local and national media had assembled. His luck or loss, depending.

The Vermont senator Bernie Sanders pitched up at the entrance to the facility shortly after 10am. The moment he stepped out of his SUV he was entirely engulfed in a tight ball of microphone booms and TV cameras.

Facebook Twitter Pinterest Bernie Sanders speaks in front of the Homestead facility in Florida on 26 June. Photograph: Rhona Wise/AFP/Getty Images

Being Sanders, none of the kerfuffle distracted him from blasting out his talking points. Enemy No 1: the private for-profit company Caliburn, on whose board of advisers sits Donald Trump’s former chief of staff John Kelly. The corporation “cares for” the migrant children at a reputed $750 each a day – giving it a cool turnover for just this one facility of close to $1bn a year.

“Corporations should not be making money by imprisoning children,” Sanders thundered, his white hair glistening at the center of his media ball.

Sanders spoke, looked over the chain-link perimeter fence as orange-hatted child detainees were led in single file between the tents, requested entry to the facility, was denied and then left. It was precisely the same routine repeated by all the presidential candidates who came before and after him.

Next up, arriving 23 minutes after Sanders had departed was Beto O’Rourke, fresh from his performance at the first bout of Democratic debates on Wednesday night. O’Rourke repeated one of the most memorable aspects of his debate appearance – he broke into spontaneous Spanish.

Standing atop a ladder better to view the child detainees on the other side of the fence, he began calling out to them. “¡Los vemos! ¡Los queremos! ¡Estamos aquí con ustedes!” he shouted, the veins on his neck distending with an effort to project. “We see you! We love you! We are here with you!”

O’Rourke invoked Robert Kennedy, a heroic figure with whom O’Rourke was once frequently compared until his polls tanked and his star waned. Kennedy said, O’Rourke reminded us, that to be an American was to be a stranger, an outcast, and to be given a home in an exile’s land.

That America, O’Rourke said, was in grave danger under Donald Trump. “If we allow this to continue,” he said, gazing over the fence at the line of children, “we will change America forever. Every day this persists, I know that it’s fundamentally changing.”

Some of the candidates have turned up at Homestead with at the head of mini-delegations. Warren arrived at the facility on Wednesday with two busloads of Miami-based supporters as her entourage.

Facebook Twitter Pinterest Elizabeth Warren outside the Homestead detention center in Florida on 26 June. Photograph: Daniel A Varela/AP

She too followed the routine, mounting a ladder as local protesters held letters aloft spelling “Shut it down” and waved banners saying “Close the camps”.

One activist managed to switch the faded baseball cap that Warren had been wearing with an orange cap like those of the detainees. It bore the logo “Home Instead”.

“The character of our nation is not the character of the president,” she said.

By the end of this week Pete Buttigieg, the mayor of South Bend, Indiana; Julián Castro, former federal housing secretary; the New York senator Kirsten Gillibrand; the California senator Kamala Harris; John Hickenlooper, former governor of Colorado; and bestselling author and spiritual healer Marianne Williamson will all have done the exact same routine, posed for the same photo ops and said many of the same things.