Jon Kyl dies at 84 after a dementia diagnosis he made public in December

Jon Kyl, the Arizona Republican who spent 26 years in Congress and later filled John McCain's Senate seat for a few months in 2018, died on Thursday at his home in Phoenix. He was 84. His family said the cause was complications of a neurological disease. In December 2025 he had announced a dementia diagnosis.

John Llewellyn Kyl was born on 25 April 1942 in Oakland, Nebraska. He won a House seat in 1986, then a Senate seat in 1994, and served three full Senate terms. He was Republican whip from 2007 until he left at the start of 2013. Colleagues called him a workhorse. Doug Ducey, the former Arizona governor who treated him as a mentor, used that word again after the death.

Western water law was one of his long files. He worked on Colorado River allocations that still shape Arizona, California and the basin states. Judiciary work was the other. In 2018, after McCain died, Ducey appointed Kyl to the vacant seat. Donald Trump had nominated Brett Kavanaugh to the Supreme Court. Kyl returned to the chamber to manage that confirmation, then left again.

The December letter

When Kyl disclosed the dementia diagnosis he quoted Ronald Reagan's letter about Alzheimer's. He said he remained a fortunate man and still trusted Arizona and the country's future. He had already stepped back from public events.

He is survived by his wife, Caryll Collins, their children John Kyl and Kristine Kyl Gavin, and four grandchildren. A family statement said he belonged to all of Arizona and had treated service as a privilege.

The record he leaves

Kyl's career ran from Reagan's presidency through Trump's first term. He watched his party change around him and stayed in the institutional lane: whip counts, water statutes, judges. He once said there is more to life than the Senate and that some people stay too long. He left on his own timetable in 2013, came back for a defined task in 2018, and then left again.

Arizona politics after McCain has been louder than Kyl's style. The obituary that matters for the state's water and court fights is not the volume of his speeches. It is the statutes and the Kavanaugh vote he helped organise. Those remain in force. The man who worked them is dead at 84 in Phoenix.