There’s little doubt about committees being a stronger force for shaping legislation in the House than in the Senate. That is why so many lobbyists and lawmakers had their ears pressed to the door Wednesday while the Republican Steering Committee started filling openings on the most influential House panels.

But when it comes to shaping national political careers, it’s the Senate where such assignments often represent the biggest value. That is why everyone already pondering the next Democratic presidential campaign, and before that, the senatorial balance of power after the 2018 midterms, has been parsing the committee rosters finalized this week.

In the House, committee plums are given out by the leadership — augmented by a few voices from the rank and file — after complex calculations about partisan loyalties, demographic diversity, future re-election prospects and fundraising prowess. (This year’s luckiest GOP and Democratic winners are supposed to be revealed by the end of the week.) With 435 members and only a relative handful of openings on prestigious panels after each election, however, most members accept the notion they must spend their legislative careers on panels that rarely make the headlines.

But in the Senate, where seniority remains a powerful internal force, the members who’ve been around a while generally claim the meatiest pickings and the newcomers are left to scrounge for the best of the rest. Still, since there are only 100 people to fill four times as many committee spots, each senator is almost guaranteed an assignment to one of the most powerful rooms.

And so career management for the savviest senators, those seeking to minimize re-election troubles or polish their résumé for a national campaign, often includes a notable committee trade-up at the start of a new Congress.