President Donald Trump’s pick for acting Department of Homeland Security secretary was a vocal defender of U.S. Customs and Border Protection officers using tear gas on migrants, including children, who attempted to circumvent authorities and approach the southern U.S. border last year.

Following the resignation of DHS Secretary Kirstjen Nielsen on Sunday, Trump announced that Kevin McAleenan, the nation’s top border security official, would serve as acting secretary. McAleenan made headlines in November when he defended the efforts of CBP agents who used tear gas on hundreds of migrants who tried to get past Mexican authorities and run toward the border near Tijuana, Mexico, during a protest. A photo of a woman and children trying to flee the area as tear gas billowed in the background went viral and sparked outrage.

“I think it’s remarkable that agents were able to resolve the situation without any serious injuries or a breach of the border,” McAleenan said during testimony before the Senate Judiciary Committee in December. He said authorities did not target young children, insisting that “agitators” hurling rocks prompted the use of the gas.

Echoing Nielsen’s response at the time, McAleenan also said the officers’ actions were effective at ending the threat of the protesters throwing rocks at CBP agents. When asked during a CNN interview why the chemical agent was used ― especially in light of children present ― McAleenan said it was “very unfortunate that parents [were] putting their children at risk and bringing them into that situation to try to rush through the border illegally.”

McAleenan was sworn into his role at CBP in March 2018 after serving as acting commissioner and in other roles for more than a decade. The Washington Post reported that McAleenan grew in prominence during President Barack Obama’s presidency, and he received the country’s highest civil service prize, the Presidential Rank Award, in 2015.

McAleenan holds a law degree from the University of Chicago and a BA from Amherst College in political science, law, jurisprudence and social thought. He supports constructing new barriers along the southern U.S. border and backed President Donald Trump’s request for funding from Congress that eventually led to the government shutdown.

When it comes to cutting off aid to Central American countries, McAleenan seems to hold different views than Trump.

Last July, McAleenan said El Salvador’s programs to improve its government, safety and education ― initiatives which are funded by the U.S. to help curb the number of migrants seeking asylum at the border ― were “working both on the security front and the economic opportunity front.”

The State Department announced last month that it was cutting aid from El Salvador, Guatemala, and Honduras, claiming the countries “set up” caravans of migrants to seek asylum at the border.