The idea behind the DACA (Deferred Action for Childhood Arrivals) program is to recognize that hundreds of thousands of migrants who were brought across the U.S. border - undocumented and often unaware - as children have grown up to accomplish wonderful things on American soil. They are top college students, nurses, and construction workers, and pillars of their local churches and neighborhoods.

But when the program to protect these young immigrants called “Dreamers” was launched during the Obama years, even the program’s biggest backers couldn’t have dreamed up a hero quite like Alonso Guillen, 31.

Guillen, an undocumented Mexican migrant who’d come to Lufkin, Texas, when he was just 14, graduated from Lufkin High School, went to church at his local Catholic parish, and - now grown up and with the protections offered by DACA - established a comfortable life working in construction and as a weekend DJ in his adopted hometown two hours north of Houston. He’d become too much of an American to watch the frightening images of flooding from Hurricane Harvey and not feel like he had to do something to help his neighbors, even after his father, Jesus, begged him not to go.

Guillen and two friends borrowed a boat, drove south, and when they reached the northern end of the flood zone in Spring, Texas, tried to rescue people trapped in an apartment complex.

It was the last act of Alonso Guillen’s too-short life. In the fast-moving waters, the boat struck a bridge and threw out its passengers. Guillen and one of his friends didn’t make it; family members searched for Guillen’s body for days until it surfaced in the subsiding waters on Sunday.

“Thank you, God,” Jesus Guillen told the Houston Chronicle, “for the time I had with him.”

At roughly the same time that the family was pulling Guillen’s corpse from the water, news reports said the Trump administration had decided to end the DACA program in six months without intervention from Congress, raising the possibility that 800,000 youths and younger adults like Guillen who’ve rooted themselves in American life as our classmates and our co-workers could lose all of that and might even be uprooted and deported back to nations they barely remember from their toddler days.

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Yet again, President Trump faced a choice between a legally complicated but undoubtedly popular program (supported by roughly two-thirds of the public) that embraced the idea of an idealistic, hopeful and welcoming America - and the grim xenophobic fears of his narrow political base. Once again, Trump went with the darkest possible vision of the country he’s supposed to lead.

Trump’s defenders say that the president is only playing politics - that in the end he’d like to continue the “Dreamer” program but that the final say should come from Congress.

And given past support for the 2010 Dream Act - upon which DACA was based - from a host of moderate Republicans, it’s not unreasonable to hope for that rarest of outcomes, salvation from Capitol Hill. But let’s be clear: Trump “playing politics with DACA” is a polite way of saying he is terrorizing decent people - people who look ahead six or seven months and don’t know whether they’ll be sitting in chemistry class or an immigration jail cell, waiting for a bus across the Mexican border.

In a not particularly shocking development, Trump’s back-in-favor attorney general, Jeff Sessions, managed to make matters worse when, sent out to do his boss’ dirty work, he could barely contain his glee in announcing that DACA had been “rescinded” for the 800,000 humans he referred to as “illegal aliens” - all while prattling on about how unlawful immigration “has put our nation at risk of crime, violence, even terrorism.”

This time last week, I was wondering if the simple humanity that was displayed again and again in Houston and its surrounding communities - the journalists who dropped their microphones to help rescue flood victims, the imams who opened their mosques to shelter the needy, and, yes, the immigrants who baked bread or trudged through four feet of water to reach their menial jobs - would change our mostly toxic national conversation. It probably has for some, but that buck has stopped well short of the White House.

It now seems the tone-deaf cruelty at 1600 Pennsylvania Avenue is set on auto-pilot. Trump showed this weekend that the former reality-show star can take enough stage direction to hug black and brown children at a hurricane shelter, but our president and his henchmen like Sessions remain incapable of truly embracing human decency, and the stubborn dignity of real Americans like the late Alonso Guillen. Hurricane Harvey, for all its destruction and heartbreak, was their opening for a reset.

There was a chance to use Houston’s remarkable diversity and the willingness of thousands of undocumented immigrants to go to work rebuilding south Texas to make a brand-new start of it, but it was naive and even foolish to think Trump or Sessions would ever seize such an opportunity. You can’t mend a heart that doesn’t want to be unbroken.

Will Bunch is a columnist for the Philadelphia Daily News.