Sen. Cory Booker (D-N.J.) said that as president, he would prioritize public schools despite his past record of supporting charter schools when he served as mayor of Newark, New Jersey.

The greatest natural resource any nation has ... is not oil gas or coal, its the genius of our children, he said at a presidential candidate forum hosted by the public-sector labor union AFSCME and co-moderated by HuffPost in Las Vegas on Saturday.

Booker also said he would fight back against Republican schemes to privatize education, which he said have been pursued aggressively in Michigan. And he noted that as a Senate candidate, he was endorsed by the New Jersey Education Association, the largest teachers union in his state.

Were seeing an assault on education that is outrageous and unacceptable, Booker said when asked about his previous charter school support.

In Michigan, Republicans have written these charter school laws in a way that I would oppose dramatically because theyre designed in a way that has no accountability, he said. He called the Michigan laws an assault on public school education as we know it.

According to the National Alliance for Public Charter Schools, as of 2016 close to 10% of Michigans public school students were enrolled in charter facilities.

As Newark mayor from 2006-2013, Booker staunch supported charter schools , which are publicly funded but operate independently of the public school systems. Booker on Saturday didnt distance himself from his charter school support, instead using it as an example of his focus on education in general.

As mayor, he said, I took responsibility for the problem and I fought for my kids.

Newark, New Jersey, is now the No. 1 one school system in all of America for beating-the-odds-schools, from high poverty to high performance, the senator said.

As part of his education agenda, Booker also said he would be recruiting an education secretary who actually attended public school in the U.S. Betsy Devos, a Michigan native who serves as President Donald Trump s education secretary and is a charter school advocate, attended a private high school.