State Rep. Bob Thorpe is ending his bid for a seat in the Arizona Senate, signaling an end to the outspoken Flagstaff Republican's time at the Legislature after next year. The move also upends the race for what could be a decisive district in the battle for control at the Capitol.

Thorpe's withdrawal from the Republican primary in his sprawling Northern Arizona district narrows the intra-party race to incumbent Sen. Sylvia Allen and Wendy Rogers, a retired Air Force officer, as well as businessman Edward Hampton, who has filed to run, too.

Meanwhile, Democrats are aiming to flip Legislative District 6, which extends from Tusayan to Rock House to Snowflake and includes reliably left-leaning Flagstaff.

Thorpe eked through to victory for a House seat with less than 600 votes last year while Allen won reelection by only 1,700 ballots. She has since been embroiled in controversy.

Over the summer, Allen was recorded telling a Republican group about declining birth rates among white people, the "browning of America" and warning that the United States would "look like South American countries very quickly."

Democrats and civil rights groups called for Allen's resignation or at least her removal as chair of the Senate Education Committee, but Republican leaders have stood by her.

Allen's changing plans frustrated some in GOP

Frustration with Allen has come from inside her own party, however.

Allen said in April that she would not seek an fourth term in the state Senate but later changed tack and said she would stay in the race.

Thorpe will reach his term limit in the House by 2020. He was first elected in 2012.

Announcing his plans Wednesday on The Jeff Oravits Show on KBTK-FM in Flagstaff, Thorpe said that he was surprised Allen did not make way for him to run for the district's Senate seat, a common practice at the Legislature. Lawmakers of the same party often switch chambers with one another when one reaches their term limit.

"Brenda Barton was very frustrated when Senator Allen refused to switch with her when Brenda was termed out in the last election," Thorpe told Oravits on Wednesday, referring to a former state representative from the same district. "And I was kind of surprised that would happen to me this time around."

Allen was appointed to the Senate to represent Legislative District 5 in 2008 and ran for the Senate seat in Legislative District 6 in 2014. She does not reach her term limit until 2022.

Thorpe had raised concerns about the Republicans' ability to hang on to the district's House seats as he reached his term limit. Democrats have recruited what he described as strong candidates for the district, including Flagstaff Mayor Coral Evans and County Supervisor Art Babbott.

But he said Thursday that the state GOP, from the governor on down, have made the district a priority. And Allen has become the face of opposition to the state schools superintendent, Democrat Kathy Hoffman.

"Senator Allen has been down at the legislature for quite a few years so I'm sure she'll do fine," Thorpe told The Republic on Thursday.

Still, Thorpe described his decision to step down as a tough one and disappointing for some in local party leadership.

Thorpe said he would run for the Coconino Board of Supervisors District 4 seat while incumbent Republican Supervisor Jim Parks will run for a legislative seat in neighboring District 7. That district is dominated by Democrats and extends from the Four Corners across the Navajo Nation to the North Rim of the Grand Canyon and south to San Carlos.

Thorpe said Parks approached him about the switch a few months ago.

Democrats look for control at Capitol

The maneuvering comes with little more than a year to go before a general election that is expected to bring large numbers of voters to the polls and a concerted effort by Democrats to win at least one chamber of the state's Republican-controlled Legislature.

Thorpe's seatmate, state Rep. Walt Blackman, R-Snowflake, is running for re-election and Jon Saline is running for Thorpe's seat.

The state House is currently split 31-29, the narrowest divide since the GOP won control in the 1960s. The state Senate is divided 17-13.

Thorpe still has one more session in the state House, though, and has committed to working on changes to the state's laws restricting local governments from regulating vacation rental homes.

Thorpe's vote for the current law has drawn ire in communities like Sedona and Flagstaff, where party homes have rankled neighbors. Residents in need of affordable rental housing also are feeling squeezed out of the market as homeowners seek tourists, not long-term tenants, through websites like Airbnb.

In turn, Thorpe has pledged to revisit the issue in the next session, as have several other legislators who have formed an ad hoc committee to craft possible fixes.

Reach reporter Andrew Oxford at andrew.oxford@arizonarepublic.com or on Twitter at @andrewboxford.