A Republican lawmaker had strong words for a top White House adviser who used Twitter to critique a GOP immigration reform proposal.

Rep. Trey Gowdy (R-S.C.), who chairs a House subcommittee on border security, called Pfeiffer a "demagogic self-serving political hack who can't even be elected to a parent advisory committee, much less Congress."

Gowdy spoke at a subcommittee hearing on the topic of how to address the legal status of the children of illegal immigrants.