Jon Kyl, a Republican from Arizona who served in both chambers of Congress for nearly 30 years, said Tuesday that he was diagnosed with dementia.

Kyl, 83, was one of the Republican Party’s most consequential Senate leaders of his era. He began his congressional career in the House of Representatives in 1987, won a Senate seat in 1994 and became a top Republican in the chamber.

In a statement released by his office, Kyl expressed gratitude for his political career.

“However, the time has come for me to withdraw from public life. I have been diagnosed with a neurological disease manifesting as dementia,” he said.

Kyl retired from the Senate in 2013 and became a lobbyist with the law firm Covington & Burling. He returned to Congress briefly in 2018 after he was appointed by Gov. Doug Ducey of Arizona to fill the vacancy caused by the death of Sen. John McCain.

Ducey, who left office in 2023, praised Kyl after the announcement, comparing him to Barry Goldwater, the former Arizona senator widely seen as the founder of the modern conservative movement.

When Kyl was chosen to fill McCain’s seat in 2018, he was viewed as acceptable to both those who admired McCain and those loyal to President Donald Trump.

Born in Nebraska, Kyl moved to Arizona at 18 to attend the University of Arizona, where he earned his undergraduate and law degrees. He was admitted to the Arizona State Bar in 1966. He also served as a lobbyist for a law firm in the state before entering politics.

The University of Arizona said after Kyl’s announcement Tuesday that it had been chosen as the steward of his papers.

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This article originally appeared in The New York Times.

By John Yoon/Peter W. Stevenson
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