When the Belgian National Congress sat down to draft a constitution after the 1830 revolution, it argued for weeks about whether the new country should have one chamber or two. The single-chamber camp won the moral argument; the bicameral camp won the vote. The reasoning was conservative in the most literal sense: the Senate was designed to brake the more progressive Chamber of Representatives. Senators had to pay ground taxes to be eligible. Only male taxpayers could vote for them. The heir to the throne was a senator by right. From 1831 onward the system tilted gradually toward democracy - universal male suffrage in 1893, the one-man-one-vote reform after the First World War, women elected as senators starting in 1936, full voting rights for women in 1948 - but the original DNA of an elite counterweight survived for a remarkably long time.

Six state reforms between 1970 and 2014 progressively dismantled the unitary Belgian state and rebuilt it as a federation of Flemish, French, and German communities and Walloon, Flemish, and Brussels regions. Each reform had to answer the same question: what is an upper house for, in a country where the real political action increasingly happens at the regional level? The 1993 fourth state reform shrank the Senate to 71 members. The 2014 sixth state reform shrank it again to 60 and stripped out every directly elected senator. Today, 50 of those 60 are picked by the regional and community parliaments, and 10 more are co-opted by the senators themselves based on the lower-house election results. The chamber became, on paper, a meeting place for the federated entities. In practice, it became a place where political parties park loyal members who failed to win seats elsewhere.

The Senate is not entirely powerless. It shares full constitutional authority with the Chamber of Representatives, which means no amendment to the Belgian Constitution can pass without a two-thirds Senate majority that also includes a majority in each language group. It mediates conflicts of interest between Belgium's parliaments - a real job in a country with seven of them. It sends delegations to interparliamentary conferences and helps the federated entities show up in EU-level discussions. It participates in appointments to the Constitutional Court, the Council of State, and the High Council of Justice. And under the EU treaties, it can flag draft European legislation that overreaches into matters better handled at the national or regional level. None of this is glamorous. None of it makes the news. All of it matters when it matters.

Until 2014, the Belgian Senate had something almost no other modern chamber retained: senators by right. The children of the king, once they turned eighteen, automatically took the constitutional oath and joined the Senate. Until Prince Philippe became king in July 2013, three of them sat in the chamber - Philippe himself, his sister Princess Astrid, and his brother Prince Laurent. They were entitled to vote starting at age 21, though in practice they almost never did, and their abstention was carefully written into the rules so they could not affect the quorum. The sixth state reform abolished the category, which was timely: when the rule lapsed in 2014, none of Philippe's children was old enough to inherit the seat anyway. A nine-century institution ended without anyone being bumped out.

Since the 2014 reform, the Senate holds about ten plenary sessions per year. Its current president is Valerie De Bue of the Reformist Movement, and she shares a curious distinction with her counterpart in the Chamber: the two of them, jointly, occupy the second position in the Belgian order of precedence, immediately behind the king himself, with the elder of the two taking priority. The Palace of the Nation, which has hosted both chambers since 1831, was built as a Council of Brabant courthouse before the Belgian state even existed. Walk past it on rue de Louvain on most days of the year and the Senate side is dark. The committees meet more often than the full chamber does. Federalism, in Belgium, has not so much abolished the upper house as turned down its lights and waited to see if anyone notices.