You might recall the bold — and reckless — declaration that Donald J. Trump made after being nominated by the Republican Party to run for president of the United States.

“I, alone, can fix it,” he said, referring to the myriad ills he said were afflicting the nation at the time.

Many of us ridiculed the nominee for that statement. No president can do much of anything “alone” without help and cooperation.

Guess what. None of us saw the crisis that is developing at this moment with a Trump administration policy that allows for children to be taken from their parents at the nation’s border. It’s a hideous policy. It is the creation of an administration that has demonized illegal immigrants, portraying them as criminals intent on murdering, raping Americans, selling them drugs.

Here’s more to ponder: Donald Trump can ease this crisis “alone,” with a signature and a phone call.

The president can halt the “zero tolerance” policy all by himself. It is not a product of a “Democrat bill,” which he has contended falsely.

It turns out the 2016 GOP presidential nominee was more truthful than we imagined at the time when he said “I, alone” can repair this or that.

If only he would act.

He has created a crisis. The president needs to fix it.