Mike Collins

Representative Mike Collins, a Trump-aligned immigration hard-liner who has drawn headlines with provocative social-media posts, is one of three top candidates in the Republican primary for Senate in Georgia on Tuesday.

Here are five things to know about Mr. Collins, 58, a second-term congressman from rural central Georgia.

1. He is running as a loyalist of President Trump. Like the two other top candidates in the Republican race, Mr. Collins has cast himself as an ally of the president, who has not endorsed a candidate in the race. Mr. Collins has some unique ties to the president: The first bill Mr. Trump signed after returning to office was a bill sponsored by Mr. Collins. The measure, the Laken Riley Act, targeted undocumented immigrants charged with nonviolent crimes for deportation. Mr. Collins’s campaign website describes him as “constant” at Trump rallies.