It’s not just House Republicans with some seats to fill on that chamber’s Appropriations Committee.

Senate Democrats as soon as this week are poised to shuffle their own slate of Appropriations subcommittee leaders due to the Energy-Water Appropriations vacancy created by the death of Sen. Dianne Feinstein, D-Calif., last year.

Some appropriations insiders are betting on Sen. Martin Heinrich, D-N.M., to take on the role, though no decisions have been made and there are other possible scenarios.

Senate Appropriations Chair Patty Murray, D-Wash., stepped into the Energy-Water subcommittee chair role on an interim basis in October, to see out the rest of the fiscal 2024 process. With that finally over, Senate Democrats are expected to move quickly to fill the slot on a more permanent basis with the fiscal 2025 cycle getting underway. 

Murray already chairs the Military Construction-VA subcommittee on top of the full committee. She was able to take on the Energy-Water panel as well last year in part because the bill had already been written and reported out of committee before she assumed the reins.

But having full-time responsibility for two subcommittees as well as the full committee would be a major lift. In addition, Senate Democrats’ rules already preclude a full committee chair from running one subcommittee if another, more junior panel member wants the slot, let alone two subcommittees.

That’s where Heinrich comes in: New Mexico has a major Energy Department footprint, including the Los Alamos and Sandia national laboratories — employing roughly 30,000 in the state — as well as an office in Albuquerque. New Mexico also has unique water issues given the state’s geography. Longtime Sen. Pete V.  Domenici, R-N.M., for years was the top Energy-Water Republican.

Heinrich said Monday that he would hold off on making his intentions known.

“It’s a very interesting subcommittee,” he said.

Heinrich is currently the Agriculture Appropriations Subcommittee chair, a position he could choose to remain in. 

One potential issue for Heinrich is that he’s also in line to be the top Democrat on Senate Energy and Natural Resources next year after Sen. Joe Manchin III, D-W.Va., leaves Capitol Hill. So he could potentially get kicked out of a subcommittee chairmanship at that point under caucus rules. But that would be the case no matter which Appropriations subcommittee he chairs.

Regardless of what Heinrich decides, Sen. Kyrsten Sinema, I-Ariz. — who last year was appointed to Appropriations to fill the vacancy left by Feinstein — appears poised to move into a subcommittee chair role if she wants it. She serves on both the Agriculture and Energy-Water panels.

Sinema is directly behind Heinrich in seniority on Energy-Water subcommittee. On Agriculture, the caucus rule would give Sinema first dibs over two full committee chairmen ahead of her in line — Manchin and Homeland Security and Governmental Affairs Chairman Gary Peters, D-Mich. 

Sinema, a centrist former Democrat who has tussled with party leaders in the past, is joining Manchin in retirement next year.