With Homeland Security Secretary Kirstjen Nielsen abruptly resigning Sunday amid a crisis on the southern border, where Border Patrol has been overwhelmed by illegal immigrants flooding into the country, President Donald Trump made the right move in announcing her replacement.

That’s according to Thomas Homan, former acting director of U.S. Immigration and Customs Enforcement, who praised the selection of Customs and Border Protection Commissioner Kevin McAleenan to replace Nielsen, saying McAleenan is “probably one of the smartest guys I’ve ever worked with.”

“He knows border issues, and he can hit the ground running,” Homan told Fox News. “He knows the border… he will start day one.”

President Trump took to Twitter Sunday afternoon to thank Nielsen for her service and announce that McAleenan will become acting director.

“Secretary of Homeland Security Kirstjen Nielsen will be leaving her position, and I would like to thank her for her service,” Trump tweeted. “…I am pleased to announce that Kevin McAleenan, the current U.S. Customs and Border Protection Commissioner, will become Acting Secretary for @DHSgov. I have confidence that Kevin will do a great job!”

….I am pleased to announce that Kevin McAleenan, the current U.S. Customs and Border Protection Commissioner, will become Acting Secretary for @DHSgov. I have confidence that Kevin will do a great job! — Donald J. Trump (@realDonaldTrump) April 7, 2019

Nielsen said in a tweet late Sunday she has “agreed to stay on as secretary through Wednesday, April 10th to assist with an orderly transition and ensure that key DHS missions are not impacted.”

I have agreed to stay on as Secretary through Wednesday, April 10th to assist with an orderly transition and ensure that key DHS missions are not impacted. — Sec. Kirstjen Nielsen (@SecNielsen) April 8, 2019

Homan was very clear about Congress being at fault for the tens of thousands of migrants flooding the border, many of them being women and children from Central America.

“We are enticing people to come,” he said.

“We need to get Congress to fix the loopholes that causes these caravans to come,” the former ICE official said, noting that “the numbers are up because half of Congress are for open borders.”

And there’s no mistaking that Homan is speaking about Democrats.

“They want to abolish ICE, they support sanctuary cities and they wonder why there is the massive numbers on the border?” he said. “Of course there’s massive numbers on the border because we’re enticing people to come.”

Stressing that there are no consequences for crossing into the U.S. illegally, he said that McAleenan “will think outside the box.”

“Kevin will put his foot on the gas,” he insisted, while recognizing that in many ways his hands will be tied by Congress.

Citing a senior U.S. official, CBS News reported that Nielsen’s departure is “part of a massive DHS overhaul engineered and directed by top Trump adviser Stephen Miller.”

It’s unclear whether her decision was voluntarily, or whether she was pressured to step down.

President Trump called migrants manipulating U.S. asylum laws a “scam” during his visit to the southern border last week.

“The system is full,” Trump said. We can’t take you anymore. Whether it’s asylum. Whether it’s anything you want. It’s illegal immigration.”

The president also signaled change was coming while speaking to reporters Friday on the White House South Lawn before leaving for California, saying “we’re going in a tougher direction,” according to CBS News.

Nielsen tweeted a copy of her resignation letter.

“This afternoon I submitted my resignation to @POTUS and thanked him for the opportunity to serve in his administration,” she said. “It’s been an honor of a lifetime to serve with the brave men and women of @DHSgov. I could not be prouder of and more humbled by their service, dedication, and commitment to keep our country safe from all threats and hazards.”