WATCH: Dem witness accuses Trump of ‘population purge,’ Kennedy fires back: ‘You trigger my gag reflex’

David Bier, a Democrat-called witness at a Senate Budget Committee hearing Tuesday, drew a sharp rebuke from GOP Sen. John Kennedy of Louisiana after accusing the Trump administration of attempting a "population purge" in the U.S.

Earlier in the hearing, Bier, an immigration policy expert at the CATO Institute, argued that both legal and illegal aliens "are a benefit to this country" because they help to reduce the national deficit.

Kennedy ripped into Bier, asking, "What planet did you parachute in from?