Sen. Mike Enzi (R-Wyo.), the chairman of the Senate Budget Committee, announced Saturday that he’ll retire in 2020, after 22 years in office.

Enzi, 75, shared his decision at a news conference at the Gillette City Hall. “I have much to get done in the next year and a half,” he said, according to the transcript of a speech he delivered highlighting what he counts as his achievements, including mine safety and pension reforms. “I want to focus on budget reform. I don’t want to be burdened by the distractions of another campaign. After this year, I’ll find other ways to serve.”

The low-key senator described the personal toll for himself and his wife, Diana, driving 500 miles around the state on weekends, 1,500 miles during recesses and hours on planes to Washington. He said he wasn’t complaining, but after more than two decades, it was time to step aside.

“I can’t do the kind of job Diana and I have been doing for another six-year term,” he said. “I was able to see my kids grow up before I went in the Senate. Now I want some grandkid time.”

Enzi’s retirement opens a seat in a solid Republican state and focuses attention on Rep. Liz Cheney (R-Wyo.), who unsuccessfully tried to challenge Enzi in the 2014 election. Wyoming Republicans privately said that Cheney, the daughter of former vice president Richard B. Cheney, is the clear front-runner, if she wants it.

But if Liz Cheney runs, she will be trading an ascendant career in the House for a relatively fresh start in the Senate. Cheney has risen in the House GOP leadership, claiming the No. 3 post uncontested after less than two years as a congresswoman. In a party that has grown desperate for prominent female voices, some Republicans are encouraging Cheney to stay in the House and try to become House speaker, if Republicans take back the majority.

In an interview with The Washington Post in November, Cheney, unprompted, mentioned that she now understood her father’s love of the House. “It’s a very special place,” she said.

For now, Wyoming Republicans believe the field is frozen in the Senate race until Cheney decides, and they do not expect an immediate decision from her. They spoke on the condition of anonymity to freely discuss private deliberations.

In a statement commending Enzi’s service Saturday, Cheney made no mention of her own aspirations.

“For more than four decades, Mike Enzi has devoted himself to serving our state and the country,” she said. “I’m privileged to have had the opportunity to work alongside him for the people of Wyoming and am proud to call him a friend.”

Enzi began his political career as Gillette mayor, then moved on to the Wyoming Legislature. He was sworn into office in 1997. Enzi has passed more than 100 bills, shepherding various budget packages through the Senate and playing a role, as a senior member of the Senate Health, Education, Labor and Pensions Committee in renewing No Child Left Behind and a bill to require health insurance companies to treat mental health as they would physical illnesses.

But his Senate tenure has played out with relatively little fanfare in a body where senior figures often become household names.

As chairmen of the Budget Committee, Enzi played a key role in getting the 2017 tax cut signed into law. But Enzi, who rarely clamored for the media spotlight, never became a face for that bill alongside President Trump and lawmakers who shepherded the measure through the House.

Over the bulk of his career, Enzi has been a steady voice advocating for the GOP’s historic platform of deficit and entitlement reforms. But since Trump came to office, he has not established himself as a public challenger to the president, as Congress has approved record budgets racking up the national debt.

Despite Enzi’s low profile, he has been viewed by his colleagues over his career as an old-guard statesman and reliable dealmaker.

Sen. John Barrasso (R-Wyo.) praised Enzi in a statement.

“Mike Enzi’s character, courage and credibility have made him a respected moral leader in the U.S. Senate. In four terms in the Senate he has never wavered in his commitment to God, family or Wyoming,” Barrasso said. “The Senate and Wyoming will miss the valued leadership of the trusted trail boss of our congressional delegation.