A boy holds a picture of Sinn Fein leader Gerry Adams. (Peter Morrison/AP)

In Thursday’s general election in the United Kingdom, Northern Ireland’s Sinn Féin was one of the parties returning to the U.K. Parliament. The party won seven of the 18 seats assigned to Northern Ireland — a record high for Sinn Féin.

Comments from Paul Maskey, the freshly elected Sinn Féin member of Parliament for Belfast West, sounded like a typical victory speech on election night: “I want to thank the electorate of west Belfast for putting their faith in me, for their confidence in myself and in Sinn Féin in greater numbers.” Although the post-election elation sounded like any other, there is one big difference: When Parliament resumes in London next week as MPs take the oath of office and begin serving in the House of Commons, the seven Sinn Féin MPs will not be joining them.

The fact that Sinn Féin MPs will not be taking their seats has become pertinent in the past 24 hours, as politicians from all parties come to grips with the hung Parliament and the new balance of power. But despite speculation that Sinn Féin could be a kingmaker in a progressive coalition, party president Gerry Adams confirmed that Sinn Féin MPs will not be taking their seats.

Why doesn’t Sinn Féin show up?

Sinn Féin practices abstentionism,” meaning Sinn Féin candidates campaign for seats in Parliament but the winners don’t take the oath of office and thus never enter the legislative chamber or vote on bills. The party adopted this policy because of its deeply held opposition to having the Parliament and government in London rule over Northern Ireland. Sinn Féin is an Irish nationalist republican party, which was the political arm of the republican movement during “The Troubles” while the Irish Republican Army (IRA) fought on the military front. All MPs are required to swear an oath of allegiance to the monarch — a pledge that is antithetical to the core beliefs of the staunchly republican party.

Sinn Féin members do actively participate in political bodies elsewhere. The party started taking up local council seats in 1983. It had once abstained from taking seats in the Republic of Ireland’s Parliament, Dáil Éireann, because it believed that the Republic’s government was also illegitimate and that the IRA’s Army Council was effectively a government in exile. However, it reversed that policy in 1986. It has also taken seats and shared power in government in the devolved Northern Ireland Assembly (a regional government within the United Kingdom) since the 1998 peace agreement that ended the years of warfare in Northern Ireland.

What does the party do?

Sinn Féin MPs carry out all of the functions of a member of Parliament short of actually entering the House of Commons. They hold meetings with their voters, deal with constituents’ concerns, make speeches and meet with politicians to advocate on behalf of their constituents. Since 2001, Sinn Féin MPs have had offices on the Westminster Estate and can claim the support and expense costs just like other MPs (although they cannot claim a salary). In fact, Sinn Féin MPs travel to London at least once a week, according to the party, to brief and lobby on behalf of their constituents.

Yet Sinn Féin is more than just a supplier of constituent services and meeting attendees. In fact, Sinn Féin MPs serve as representatives through their very absence. Political theorists may assume that representation involves being present inside a legislative chamber, but the case of Sinn Féin demonstrates that such presence is not a necessary condition.

Political theorist Andrew Rehfeld offers one way to think about this. He argues that representation occurs when “there is some Function that requires a Representative,” with a “Function” being the job that the representative is supposed to do on behalf of the represented. We normally think of that job as lawmaking and deliberation in the legislative chamber. But if the represented agree that the legislative chamber is not a legitimate body (as in the case of nationalist republican Sinn Féin voters), the function required of the representative is instead to demonstrate this through abstention and to advocate via other means. This is precisely what Sinn Féin does in the case of Westminster.

The most powerful — and for Sinn Féin, most important — example of an abstentionist Irish republican is Bobby Sands, who was MP for Fermanagh and South Tyrone in 1982. Sands was serving time in Long Kesh prison for activities related to the Irish Republican Army. He and fellow IRA prisoners went on a hunger strike to protest that they were not being treated as political prisoners. Nine days into the hunger strike, the sitting MP for the constituency died suddenly, opening up the seat. Sands stood in the by-election and won, garnering more than 30,000 votes. His supporters hoped that an electoral win would draw attention to his cause and that then-Prime Minister Margaret Thatcher would grant the prisoners’ demands to avoid the death by starvation of a sitting MP. But Thatcher did not waver, stating, “Crime is crime is crime. It is not political.”

The case of Bobby Sands demonstrates the powerful symbolism that comes with electing a member of Parliament and the wide range of functions that this representative’s message can serve. Sands remains a powerful figure in the mythology of the republican movement — the party chose to launch this year’s campaign from Fermanagh and South Tyrone, for example, and often refers to Sands’s election victory and subsequent death.

Don’t voters care?

Sinn Féin supporters — virtually all of whom are Catholic, nationalist and republican inclined — don’t stop supporting the party because of its abstentionism.

As this graph shows, the rates of support for Sinn Féin in Westminster elections have been consistently similar to the shares they get for other offices where the party does take up their seats. That suggests that voters don’t penalize the MPs for not showing up and that instead they endorse the mode of representation that Sinn Féin opts to practice.

Opponents, however, point to Sinn Féin’s abstentionism as a reason to cast votes elsewhere. Some of Sinn Féin’s rivals have issued statements making arguments such as, “While Sinn Féin have shouted from the sidelines, we have used our influence in Parliament to fight Northern Ireland’s corner.”

The evidence suggests this has little effect on those who would normally support Sinn Féin. In continuing to vote for abstentionist MPs, Sinn Féin voters in Northern Ireland affirm the representative act employed by their MPs, who are notably absent on their behalf.

 The future of Sinn Féin and Westminster?

Despite speculation and pressure in the wake of a close election, the party has remained steadfast in its commitment to abstentionism, and there seems no reason this will change in the near future. The combination of the symbolic and principled gains that come from abstentionism is important, especially as the republican movement tries to hold itself together. Some more hard-line republicans believe that the nationalist movement has already compromised too much by giving up the armed struggle, and Sinn Féin’s leadership has good reason to want to stop them from defecting. Furthermore, the party believes, abstentionism isn’t so politically costly.

Sinn Féin MPs often argue that Westminster simply is not a place where Northern Irish MPs will ever have any meaningful power. Northern Ireland’s MPs make up just 18 of the 650 members of Parliament (amounting to less than 3 percent of the House of Commons). A best-case scenario would see Sinn Féin winning eight seats (all those constituencies with sufficient nationalist populations), and even then they would hold just over 1 percent of seats. In a parliament dominated by strong parties, and in a system where individual MPs can virtually never propose bills, there is not a lot that Sinn Féin could do. The possibilities of forming part of a workable coalition are also slim, as mainland U.K. parties would find it politically difficult to accept Sinn Féin’s support. Given all of this, and the gains in support and legitimacy from abstaining, Sinn Féin doesn’t look set to show up in Britain’s Parliament any time soon.