Across the Capitol, the head of the Border Patrol emphasized much the same message to a hearing of the Senate Judiciary Committee.
"From the experience of our agents and officers on the ground, it is indeed both a border security — and a humanitarian — crisis, " said Kevin McAleenan, the Border Patrol chief.
"In fact, the Border Patrol has already apprehended more families crossing illegally than during all of last year," McAleenan added.
Democrats clashed with administration officials on the figures being used by both the Administration and the President, arguing illegal immigration flows were much larger two decades ago.
"I want to know is what the President said, is it accurate or not?" pressed Rep. Jim Langevin (D-RI).
"I just don't know the context of his statement," Nielsen said, parrying Langevin's questions.
The hearings on border security came as Senate Republicans wrestled with a House-passed resolution to block President Trump's national emergency declaration in order to bypass Congress and shift more money into a border wall.
A vote in the Senate is likely next week.
"We're all concerned about the constitutional issues here," said Sen. Ron Johnson (R-WI), one of many GOP Senators not thrilled with the precedent set by the President's decision. "But we are probably even more concerned about border security."