PHILADELPHIA — Rep. Lou Barletta, a close congressional ally of President Donald Trump, won the Republican nomination for U.S. Senate Tuesday, setting up a general election contest with Democratic Sen. Bob Casey that is likely to serve as a referendum on the White House.

Barletta defeated State Rep. Jim Christiana, of Beaver County, who was endorsed by several fellow members of the state Legislature.

Casey was unopposed in his party’s primary; he is running for a third term in the Senate.

Before winning election to Congress in 2010, Barletta was mayor of Hazelton, Pa., where he was nationally renowned for fighting what he considered an invasion of undocumented Latino immigrants. The ordinance Barletta pushed through, fining those who rented to illegals and yanking business licenses from companies who employed undocumented workers, was declared unconstitutional, but he became what many consider the godfather to Trump’s anti-immigrant politics — the congressman was an early Trump backer in 2016 and was considered for a position in the Cabinet.