PHOENIX – Jon Kyl, once one of the most powerful Republicans in the U.S. Senate, will return to Capitol Hill to succeed the late Sen. John McCain.

Gov. Doug Ducey unveiled the 76-year-old as McCain’s successor at a 1 p.m. ET news conference at the Arizona Capitol, after notifying McCain’s wife, Cindy, and other key political figures of his decision.

Cindy McCain tweeted her approval: "Jon Kyl is a dear friend of mine and John's. It's a great tribute to John that he is prepared to go back into public service to help the state of Arizona."

Kyl, who served alongside McCain during his 18 years in the U.S. Senate, will fly to Washington, D.C., following Ducey’s announcement. He retired in 2013 after rising to become the second-highest-ranking Republican senator.

Kyl has agreed to serve at least through the end of the year, a representative for Ducey said. If he opts to step down after the end of the session, the Republican governor would be required to appoint another replacement, the aide said.

The Arizona governor, who has long called Kyl a mentor, contacted the former senator in the hours following McCain’s Aug. 25 death. The two have forged a close bond and are like-minded, pro-growth conservatives.

Ducey sought someone who could quickly step into the seat to wrap up McCain’s unfinished business, the governor’s aide said. Kyl brings a depth of knowledge on issues key to Arizona, from water and natural resources to Native American relations.

He is respected among seasoned Republicans and is leading President Donald Trump’s Supreme Court nominee, Brett Kavanaugh, through the confirmation process. Last year, Kyl was the “sherpa” for Jeff Sessions’ contentious nomination to become attorney general.

Ducey: 'No one in Arizona more prepared' than Kyl

“There is no one in Arizona more prepared to represent our state in the U.S. Senate than Jon Kyl,” Ducey said in a statement. “He understands how the Senate functions and will make an immediate and positive impact benefiting all Arizonans. I am deeply grateful to Senator Kyl for agreeing to succeed his friend and colleague of so many years.

“Every single day that Jon Kyl represents Arizona in the United States Senate is a day when our state is being well-served.”

Kyl represented Arizona in the U.S. Senate from 1995 through Jan. 3, 2013. There, he served as minority whip, the second-highest position in the Republican conference. Before ascending to the Senate, he served in the House of Representatives from 1987 to 1995.

The decision had weighed on Ducey’s mind since last year, when McCain received his brain-cancer diagnosis. The governor refused to publicly discuss any potential appointment and condemned those lobbying for McCain’s seat while the late senator was still serving.

That changed on Aug. 25 in the hours following McCain’s death. In a conversation with Kyl, the governor told him he wanted to name him as McCain’s successor and that Kyl “was the best person to take this seat,” the aide said.

Kyl got back to Ducey the next day after consulting with his wife. He told the governor he would be willing to serve until at least the end of the year.

“He felt a sense of service, largely because it was John McCain’s seat and he had served with him for so long,” the aide said.

Kyl could assume office Tuesday night

Ducey will submit a certificate of appointment to the U.S. Senate secretary Tuesday. An aide is flying the paperwork to Washington, D.C., and will hand-deliver it to the secretary’s office.

Kyl could be sworn in as early as Tuesday night, though Wednesday is more likely, the aide said.

Kyl will return to a chamber where Republicans narrowly hold control and where votes can be unpredictable.

On Tuesday, the chamber began deliberating the Kavanaugh nomination. A Senate committee hopes to vote later this month to send Kavanaugh’s nomination to the full Senate to get him on the bench before the midterm elections.

Democrats are protesting Trump’s selection and the process Republicans are using to vet Kavanaugh.

Kyl and Ducey met when Ducey first considered running for office, and the governor has said he views Kyl as a model public servant.

After leaving the Senate, Kyl joined the high-powered Washington, D.C., law firm Covington & Burling. As senior adviser, he helps clients on issues ranging from tax, health care, defense, national security and intellectual property.

In 2006, Time magazine named Kyl one of America's 10 best senators.

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