Sen. Jon Kyl, is resigning from the seat he was appointed to less than four months ago following the death of John McCain, Gov. Doug Ducey announced Friday, a development which gives Ducey a second opportunity to fill the position.

Kyl, 76, had said he was only serving through the end of the year. His resignation is effective Dec. 31 and forces a pivotal decision by the state’s Republican governor.

That’s because voters in 2020 will get to decide who fills McCain’s seat for the final two years of its six-year term. Democrats picked up Arizona’s other Senate seat in November and are already targeting the state in 2020 as part of their possible path to re-taking control of the Senate, increasing the pressure on Ducey to select someone who can hold the seat for the GOP.

Ducey said he will pick a replacement “in the near future.” His office has been typically tight-lipped about who might fill the seat, leading to frenzied speculation in Arizona and Washington.

There may be pressure on Ducey to select a woman, because the three most prominent possible Democratic challengers are men. U.S. Rep. Ruben Gallego, former astronaut and current gun control advocate Mark Kelly and former state Attorney General Grant Woods, who left the GOP to become a Democrat this year, have all mulled running for the seat in 2020.

The most prominent Republican politician whose name has been floated is Rep. Martha McSally, who just lost a race for the state’s other Senate seat to Democrat Kyrsten Sinema last month. A former air force colonel who was mentored by Kyl, McSally has drawn criticism from some Republicans for running a campaign that focused on her closeness to President Donald Trump and tried to portray Sinema as a radical liberal.

Still, McSally only lost the race by two percentage points in a bad year for Republicans, and she’s long been seen within the party as a possible senator. Other Republican women whose names have been floated do not have her experience running in competitive elections, especially statewide.

They include Eileen Klein, a former health care executive appointed state treasurer by Ducey last year. She did not run for re-election. Some Republicans have also speculated about an appointment for Barbara Barrett, a former Ambassador to Finland and businesswoman who unsuccessfully ran in a GOP gubernatorial primary in 1994.

Some Republicans have urged the appointment of McCain’s widow, Cindy, to the seat. Notably, Ducey did not select her in the weeks after the senator’s death, and there remains widespread animosity toward the McCain family from the GOP’s conservative base.

One of the most often-mentioned names is Ducey’s chief of staff, Kirk Adams, a onetime state lawmaker who resigned from the governor’s office on Nov. 26 and whose last day working for Ducey was Friday. Other names that have surfaced include Bill Montgomery, who leads the top prosecutorial office in Maricopa County, the state’s largest, and former Rep. Matt Salmon.

Ducey’s selection of the well-respected Kyl following McCain’s Aug. 25 death allowed him to dodge the controversy over a replacement during his own re-election campaign. But Kyl, who had previously served in the Senate for Arizona, made it clear he only agreed to the appointment out of a sense of duty and had no plans to stay in the job for long.

Kyl’s brief resignation letter said he decided to resign at the end of 2018 so that Ducey’s new appointee “can begin the new term with all other senators in January 2019 and can serve a full two (potentially four) years.”

Kyl noted that when he accepted Ducey’s appointment that he agreed to serve through December and then re-evaluate whether to serve longer.

“Senator Kyl didn’t need to return to the Senate,” Ducey said in a statement. “His legacy as one of Arizona’s most influential and important political figures was already without question. But he did return, and I remain deeply grateful for his willingness to step up and serve again when Arizona needed him. I wish him and his family all the best.”

McCain died at age 81 at his ranch near Sedona, Arizona just over a year after he announced he had glioblastoma, an aggressive brain cancer that came with a dire diagnosis.

(AP)