Stephen Miller arrived on Capitol Hill Thursday to brief Senate Republicans on the White House's border wall request.

A bitter feud is escalating between Republican Sen. Rand Paul and Donald Trump’s top border official, injecting uncertainty into Congress’s attempt to pass the administration’s signature policy bill this month.

White House deputy chief of staff Stephen Miller clashed Thursday with GOP senators over increased border wall funding in President Trump’s “big beautiful bill” — as some lawmakers look for deeper cuts than their House colleagues to reduce the federal deficit.