U.S. Homeland Security Secretary Kirstjen Nielsen made it clear: Only Congress can fix the situation regarding the policy that enabled Border Patrol and Immigration and Customs Enforcement agents to separate children from their parents at the border.

The president of the United States, Donald J. Trump, said the same thing.

So did the White House press office.

What, then, happened today? The president signed an executive order doing the very thing he and his aides could be done only by congressional fiat.

Was the president lying? Did he tell the nation’s DHS secretary to lie? Did the secretary lie on her own, all by herself?