(Sarah Binder is a professor of political science at George Washington University and a senior fellow at the Brookings Institution. She has granted permission for Batten to repost her essay, which appears in The Washington Post under the headline “This is What Orrin G. Hatch’s Retirement Means for the Senate.”

Craig Volden is co-director, with Alan Wiseman of Vanderbilt University, of the Center for Effective Lawmaking.

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Sen. Orrin G. Hatch of Utah, the longest-serving Republican senator, has announced at age 83 that he will not seek an eighth term. Analysts suggested late last year that he would be vulnerable to a primary challenge should he seek the GOP nomination for another term, and in a poll last summer an overwhelming majority of Utah voters suggested it was time for Hatch to step down.

As others consider the electoral implications of Hatch’s announcement, consider these implications for the Senate when Hatch retires later this year.

It’s still your grandpa’s Senate

The Senate will remain a geriatric chamber even after Hatch’s departure. As the figure below shows, the average senator is roughly 10 years older than in 1981, making the current Senate “among the oldest” in U.S. history.

Eight octogenarians serve in the Senate, The Washington Post’s Paul Kane noted last month. A handful of septuagenarian senators legislate alongside them. That’s unusual historically, though hardly surprising. In the Senate’s first century there were shorter life spans and fewer career lawmakers, which also made octogenarians rare in the body’s second century.

As Kane pointed out, every elderly senator occupies a key committee leadership post. And the chamber has felt the consequences. The Republican policy agenda was slowed in some way this past year by their elderly colleagues’ injuries, illnesses and absences. Hatch’s departure will do little to resolve such problems.

[The Senate just made it a lot easier for Trump to appoint federal judges — over Democrats’ objections]

Goodbye to Senate lawmakers (and cowboys)

According to new work by political scientists Craig Volden and Alan Wiseman, the number of truly effective Senate lawmakers has dropped markedly in recent years. Hatch’s departure furthers that decline.

Hatch is best known for his legislative partnership with the late Democratic Sen. Ted Kennedy of Massachusetts. Despite being ideological opposites, they managed a friendship that yielded bipartisan, landmark public health laws: health insurance for children in low-income families known as S-CHIP and aid for low-income, uninsured victims of HIV/AIDS and their families. With then-Rep. Henry Waxman (D-Calif.), Hatch forged another legislative partnership to produce the Orphan Drug Act and create the modern generic drug industry. Even in the hyperpartisan Senate of recent years, Hatch helped secure Senate passage of a bipartisan, comprehensive immigration bill in 2013.

For better or for worse, Hatch also excels at exploiting the rules to block major legislation. As a freshman in 1978, the senator launched a filibuster and nearly derailed Democrats’ landmark labor law to modernize the Federal Reserve during an ailing economy. More recently, he has been the strongest defender of the nutritional supplements industry. Scientist and consumer critics of the industry say Hatch has worked for decades to derail legislative and regulatory efforts that would empower the government to block unsafe products from markets that make unproven claims about their health benefits.

Hatch has at times been a constructive legislative partner with Democrats and at other times an ardent partisan foe. Neither is common in today’s more partisan and centralized Senate, where party leaders tend to steer and advance the agenda. That leaves little legislative leeway for senators such as Hatch to make their mark on policy. That perhaps contributes to why Hatch has failed to secure the future of his prized S-CHIP.

Get ready for musical chairs (but every senator gets a seat)

And so, get the music ready. As Roll Call helpfully games out for us, if Grassley moves to the Finance Committee, he must step down as chair after two years, given his four prior years as chair. If he stays at judiciary, Sen. Michael Crapo (R-Idaho) could move to chair the Finance Committee, and Sen. Patrick J. Toomey (R-Pa.) could capture the Senate Banking Committee chair.

What’s the point? Republicans have a deep bench of older senators with long careers and years of Senate experience. But they’ve made a rule on their committee chairs that likely limits their legislative prowess: Wiseman and Volden show that longer-serving chairs tend to be more effective lawmakers. Imposing term limits on GOP Senate committee chairs might explain the recent decline in their effectiveness.

Such limits could kneecap expertise, weaken institutional memory and further empower party leaders—making it harder for senators to engage in constructive lawmaking at which senators such as Hatch once excelled.