McCain successor Jon Kyl leaving Senate on Dec. 31

Dec. 14 (UPI) -- Republican Arizona Sen. Jon Kyl will resign from the Senate on Dec. 31, the office of Gov. John Ducey announced Friday.

The resignation sets up a second appointment by the Republican Ducey, who chose Kyl to fill out the remainder of Sen. John McCain's six-year term that began in 2016. McCain held the seat for more than 31 years until his death in August.

By the time of his resignation, Kyl will have served in the seat for just over four months. He was elected to the Senate in his own right and served between 1995 and 2013.

By law, Arizona's next senator must be a Republican, and Ducey's office said the nominee "will be announced in the near future."

"When I accepted your appointment, I agreed to complete the work of the 115th Congress and then reevaluate continuing to serve," said a letter from Kyl to Ducey Thursday. "I have concluded that it would be best if I resign so that your new appointee can begin the new term with all other Senators in January 2019 and can serve a full two (potentially four) years."

The Senate seat will be up for grabs in a special election in 2020, and the winner will serve the last two years of McCain's term.

Kyl worked with McCain for 18 years and became the second-highest ranking Republican in the chamber. He retired to work as a lobbyist in the private sector. It's unclear if he intends to return to that position.

Ducey has not mentioned a preferred replacement for Kyl, but Senate Majority Leader Mitch McConnell has said he hopes Rep. Matha McSally is appointed. McSally narrowly lost the November election for Arizona's other Senate seat to Democrat Krysten Sinema, who will be sworn into office on Jan 3. Others reported to be under consideration include Kirk Adams, Ducey's former chief of staff, and state Treasurer Eileen Klein.