Homeland Security Secretary Kirstjen Nielsen is sworn in as she testifies before the House Homeland Security Committee on border security on Capitol Hill in Washington, DC, March 6, 2019. (Photo by Jim WATSON / AFP)
Washington CNN  — 

Homeland Security Secretary Kirstjen Nielsen and House Democrats sparred Wednesday over the Trump administration’s controversial immigration policies that resulted in children being separated from their parents and President Donald Trump’s declaration of a national emergency.

Nielsen defended the administration’s “zero tolerance” policy, which called for the criminal prosecution of adults crossing the border illegally and, as a result, the separation of families. Democratic lawmakers grilled the secretary over the policy, asking her when she knew about it and whether it was intended to deter migrants from approaching the southern border.

In all instances, Nielsen took a defensive stance, arguing that it was not policy, but law, referring to the criminal prosecutions.

“We enforce the law,” she told Rep. Kathleen Rice.

Nielsen has previously testified that the department “never had a policy for family separation.”

On Wednesday, she said the policy wasn’t intended to be a deterrent to families crossing the border. But in January, Sen. Jeff Merkley, D-Oregon, released a 2017 memo drafted by senior officials in the Department of Homeland Security and the Justice Department detailing the plans.

Under a section dubbed “short term (next 30 days) options,” the memo says: “Separate Family Units. Announce that DHS is considering separating family units, placing the adults in adult detention and placing the minors under the age of 18 in the custody of HHS as unaccompanied alien children.”