Retirements will substantially reshuffle the defense panels’ rosters in the next Congress, and the Nov. 8 elections will trigger still more upheaval — including big ones if Republicans take the majority in one or more of the chambers.

The changes fall into three categories: definite, likely and possible. 

The definite changes are the retirements. The likely changes are those triggered by what appears as of now to be a probable Republican takeover of the House, if not the Senate. And the possible changes are those affected by the outcome of tight races and the impact of decisions made outside the committees about leadership posts. 

Here’s a look at the minimum changes to look for on the defense authorizing and appropriating panels, based on conversations with aides and already public knowledge. 

House Armed Services Committee

If the GOP wins the House majority — which appears both likely and likelier than their winning the Senate — Republican Mike D. Rogers of Alabama would chair Armed Services, taking over from Democrat Adam Smith of Washington. Smith would stay on as chair if Democrats keep control of the chamber and would switch to ranking if they do not.

Regardless of what happens in the Nov. 8 elections, the top ranks of House Armed Services Committee Democrats are going to be overhauled by retirements. Every new Congress sees changes, but it is rare for so many senior members of one party on one committee to retire simultaneously — and the Democratic side of the House Appropriations Defense Subcommittee is also facing major roster changes.

In fact, Democrats who chair three of the seven House Armed Services subcommittees are retiring: Jim Langevin of Rhode Island, Jim Cooper of Tennessee and Jackie Speier of California. Other committee members who are retiring: Anthony G. Brown of Maryland, who is running to be that state’s attorney general, and Kai Kahele of Hawaii, who lost a bid for governor in the primary election. 

Three other Democrats on the committee who have strong defense bona fides and have been known to sway debates on the committee would not return if they were to lose closely contested reelection races. They are Elissa Slotkin of Michigan, Elaine Luria of Virginia and Jared Golden of Maine.

Republican ranks on House Armed Services are, barring reelection losses, not likely to change as much. Three GOP members are definitely leaving. The most senior of these is Vicky Hartzler of Missouri, the ranking member of the Tactical Air and Land Forces panel who lost a Senate bid in the party primary. Also departing is Mo Brooks of Alabama, who is retiring, and Liz Cheney of Wyoming, who lost in her district’s GOP primary.  

Jim Banks of Indiana, the ranking member of the Cyber, Innovative Technologies and Information Systems panel, is said to be running for Republican whip, and he would in all likelihood consequently forgo a chairmanship or ranking member spot on Armed Services.

Michael R. Turner, R-Ohio, will be a senior member of Armed Services but not a subcommittee chair or ranking member, because he will be either chairman or ranking member of the Intelligence Committee.

House Appropriations Committee

If the GOP wins the House, Ken Calvert, R-Calif., would, it seems, become chair of the Defense Appropriations Subcommittee, taking over from Democrat Betty McCollum of Minnesota, who is expected to remain chair if Democrats manage to keep their majority.

Democratic ranks on the Defense money panel are thinning and may get thinner still. At least four of the panel’s 10 Democrats — and perhaps up to six of them — will be gone next year. Cheri Bustos of Illinois, Ann Kirkpatrick of Arizona, Tim Ryan of Ohio and Charlie Crist of Florida are retiring of running for other office. And two more Democrats — Marcy Kaptur of Ohio and Henry Cuellar of Texas — are locked in tough reelection battles.

The full committee leadership posts are not expected to change. The top Democrat is Rosa DeLauro of Connecticut and the top Republican is Kay Granger of Texas.

Senate Armed Services Committee

If Republicans win the Senate majority, Roger Wicker of Mississippi, who is poised to take over for the retiring James M. Inhofe of Oklahoma as the top GOP member of the committee, is well positioned to be chairman. If Democrats keep their Senate majority, on the other hand, Jack Reed, D-R.I., would stay on as chairman and Wicker would in all likelihood be the ranking member.

Few other changes seem likely on the committee with one notable possible exception: Democrat Mark Kelly of Arizona is facing a competitive reelection contest. 

Senate Appropriations Committee

If the GOP wins the Senate, Susan Collins, R-Maine, would take over from the retiring Richard C. Shelby, R-Ala., as chair of both the Senate Appropriations Committee and its Defense panel, as CQ reported in October.    

If Democrats retain control, the Appropriations Committee chair would change from Patrick J. Leahy of Vermont, who is retiring, to Patty Murray of Washington.

On the Senate’s Defense appropriations panel, Jon Tester, D-Mont., is expected to stay chair if Democrats retain Senate control.

Besides Shelby and Leahy, the only other retirement from either party on the Senate’s Defense appropriations panel is that of Missouri Republican Roy Blunt.