Parliament Buildings, the long white limestone block on a hill in east Belfast where the Assembly meets, was designed for a different parliament. Architect Arnold Thornely's portico-fronted neoclassical pile was opened in 1932 to house the old Parliament of Northern Ireland - a body that was abolished in 1973 after 51 years of unbroken Ulster Unionist Party majority rule. The building sat largely unused for a quarter-century until the Good Friday Agreement of 1998 brought it back into service. The new Assembly that occupies it is constitutionally different: 90 members elected by single transferable vote from 18 five-member constituencies, ministers selected by the D'Hondt method to guarantee proportional representation across the largest parties, and a 'petition of concern' mechanism allowing any 30 MLAs from two parties to require a cross-community vote on any contentious motion.

The Assembly's defining feature is that government is mandatory coalition. The First Minister comes from the largest party of the largest community designation; the deputy First Minister - equal in power despite the title - comes from the largest party of the next-largest designation. The two posts run as a joint office, indivisible: if either resigns, the other automatically loses theirs. Ministerial portfolios are distributed by D'Hondt method, meaning every significant party is entitled to ministers. The Minister of Justice requires cross-community support to be appointed. The system is consociational - designed to make either community's outright veto impossible while making either community's outright exclusion equally impossible. The trade-off is that any one major party can collapse the entire institution by walking out. The DUP did this in 2017 and again in 2022. Sinn Fein did it in 2002. Each time the consequence was the same: years of political vacuum, Westminster taking over by Order in Council, civil servants making decisions no minister had authorised.

Of the 28 years between the Assembly's first election in June 1998 and the time of writing in 2026, the institution has been suspended or non-functional for more than seven years total. There were short technical suspensions in 2000 and 2001. The longer outages tell the bigger story. From October 2002 to May 2007 - four years and seven months - the Assembly sat empty after unionist parties withdrew over allegations of an IRA intelligence operation at Stormont itself. From January 2017 to January 2020 - three years - it sat empty after Sinn Fein deputy First Minister Martin McGuinness resigned over the Renewable Heat Incentive scandal, a botched green-energy subsidy that paid companies more for burning wood pellets than the pellets cost. From February 2022 to February 2024 - two years - it sat empty after the DUP withdrew in protest at post-Brexit trading arrangements that put a regulatory border in the Irish Sea. Each suspension required complex negotiations, often with prime ministers and taoisigh in the room, to end.

When the Assembly is functioning, it legislates on what are called 'transferred matters' - any field of public policy not explicitly reserved to Westminster. That includes health, education, agriculture, environment, justice (transferred in 2010), infrastructure, the economy, and community development. The 2019 budget, when Westminster passed it for Northern Ireland during a suspension, was £14 billion - a measure of how much money the Assembly normally decides how to spend. Westminster retains 'excepted matters': the Crown, defence, foreign affairs, immigration, taxation, currency, national security. The Assembly cannot raise its own taxes. It can pass laws but they can be struck down by courts if they violate the European Convention on Human Rights, exceed devolved competence, or discriminate on grounds of political opinion or religious belief. In 2019, during one of the long suspensions, Westminster legislated to legalise same-sex marriage and decriminalise abortion in Northern Ireland - matters most observers expected the Assembly itself would eventually have addressed if it had been sitting.

The 2022 election produced a result no one in 1998 would have predicted: Sinn Fein became the largest party in the Assembly for the first time in its history. Under the post-2006 rules, this meant Sinn Fein would nominate the First Minister - a position that, although equal in power to the deputy First Minister, carries enormous symbolic weight. The DUP refused to enter government for two years rather than accept this. When the Executive finally re-formed in February 2024, Michelle O'Neill became the first nationalist First Minister of Northern Ireland and Emma Little-Pengelly her DUP deputy. Whether that arrangement marks a permanent shift or just one cycle in an oscillating system is the central question of Northern Irish politics in the late 2020s. The cross-community Alliance Party - designated 'Other' - now holds 17 seats and has been arguing, with growing support, that the Nationalist/Unionist/Other designation system itself should be retired. The Assembly was built for two communities. Increasingly it serves three.