NASHVILLE (AP) — An exodus of more than two dozen state lawmakers means new faces are running for the Republican-led Tennessee General Assembly, setting up primary fights that could have early implications on the jockeying to become the House's new leader.

Eighteen Republican and seven Democratic incumbents in the House won't be running again. They include Republican Speaker Beth Harwell of Nashville and Democratic Minority Leader Craig Fitzhugh of Ripley, who are both vying for governor.

Republican House Majority Leader Glen Casada of Franklin, the second-ranking House member, has acknowledged his interest in running for speaker. He hopes his efforts to spread out PAC donations in Republican primaries, at least in part, will bolster his leadership ambitions in a chamber where Republicans hold a supermajority.

Other possible speaker candidates include Speaker Pro Tempore Curtis Johnson, a Clarksville Republican, and Rep. David Hawk, a Greenville Republican.

In the House, 86 of 99 seats are contested, with GOP primary battles in 33 districts and Democratic primary contests in 21 districts. Others are unopposed in the primary but have general election contests looming in November.

A total of 18 seats are on the ballot in the Senate, where the GOP has a supermajority.

The senators not seeking re-election are Democrats Lee Harris of Memphis and retiring Thelma Harper of Nashville; and Republican Bill Ketron of Murfreesboro. Harris, the Democratic leader in the Senate, and Ketron, the GOP caucus leader, are both contending to become mayors in their respective counties.

Two more senators may not be back: GOP Majority Leader Mark Norris of Collierville has been awaiting U.S. Senate confirmation as a federal judge for months, and Sen. Mark Green, R-Clarksville, is vying for an open U.S. House seat.

While some sitting lawmakers bolt for the door, other familiar faces are trying to make their way back.

Former state Sen. Stacey Campfield is among the five Republicans battling in a primary for an open Knoxville-area House seat. Two Democrats are seeking their party's nomination.

Campfield drew national attention — and some backlash from fellow Republicans — for polarizing comments and controversial social issue bills. He lost in a GOP primary in 2014. In a blog post, Campfield once likened the insurance requirement under President Barack Obama's health care law to the forced deportation of Jews during the Holocaust, drawing bipartisan condemnation.

In 2011, he was the sponsor of a failed bill that sought to ban teaching about gay issues in public schools.

In another Republican House primary, former state Sen. Mike Williams is challenging Rep. Jerry Sexton, who helped pass a law to create a monument to the unborn and pushed to make the Bible the official book of Tennessee, one of the few bills Republican Gov. Bill Haslam has vetoed.

Williams, who had been at odds with then-Senate GOP Speaker Ron Ramsey, changed his party affiliation to independent in 2007 and lost his 2008 re-election. He became mayor of Union County in 2010. Grainger County Commissioner James Acuff rounds out that GOP primary field.

Republican Rep. David Byrd of Waynesboro has no primary opponent.

Byrd was accused by three women in a media report March 27 of sexual misconduct as their high school basketball coach several decades ago. He automatically advances to the November general election, where he will face Democrat Frankie G. Floied of Hohenwald in a Republican-tilted district.