RALEIGH, N.C. — A key advocate in the North Carolina House for expanding gun rights and barring immigrant “sanctuary cities” plans to leave the legislature later this month, saying Friday that he needs to be at home for his family.

Three-term Republican Rep. Chris Millis of Pender County confirmed his decision to resign effective Sept. 15.

In a posting on his website, Millis said his decision was based solely on spending more time with his wife and three young children, and it “has nothing to do with any other assumptions that individuals may want to manufacture.”

“My wife, three children, parents, other immediate family, and my employer have sacrificed so much so I could serve in Raleigh,” Millis wrote, leaving open the possibility of public office again “at the proper time in accordance to God’s will and direction.”

Millis, 34, was first elected in 2012 to the 16th District seat. In time the civil engineer became a leader in a group of 20 or so hardline conservatives who sometimes tangled with fellow Republicans over spending and social issues. House Speaker Tim Moore said Millis’ departure marks the loss of one of the chamber’s “brightest and hardest-working members.”

This year, Millis was chief sponsor of a measure that would eliminate the need for a permit to carry a concealed handgun where it’s currently permissible to openly carry a gun. The measure passed the House despite several “no” votes from fellow Republicans but hasn’t been heard in the Senate.

Millis also was a primary sponsor of a 2015 law signed by then-Gov. Pat McCrory that in part bars local governments from approving “sanctuary cities” policies preventing a person from being asked their immigration status.

“At every turn, my priority was to refocus government on its proper role and to limit it to its intended purpose, so we as individuals can have the greatest opportunity to be free and pursue our own interests,” he wrote.

Millis recently led an effort — unsuccessful, so far — to impeach Secretary of State Elaine Marshall, a Democrat, based on his allegations her office issued notary public commissions to hundreds of people living in the U.S. illegally. Marshall has said she’s done nothing wrong and followed state and federal laws and policies.

In an email, Millis said it would be a “failure of the legislative branch” if colleagues did not pursue the allegations swiftly.

State Democratic Party Chair Wayne Goodwin, however, said Millis “attacked, belittled and dragged through the mud hardworking public servants” and “pushed far-right policies that have made our state less safe.”

Local Republicans will choose someone to serve out Millis’ term through the end of 2018. A redistricting map finalized this week would alter the district to match part of Columbus County — not Onslow — with Pender but keep it heavily Republican.