The prospect of a new Assembly election is a cause of dismay for Northern Ireland’s political classes who had thought they were relatively safe from voters until local government elections in 2019.
Given that the Assembly was elected only last May, MLAs would not have been up for re-election until 2021. And the landscape for the coming election, if it happens, will be familiar but different.
Following the 2014 Fresh Start Agreement, the North's constituencies will now elect only five members to Stormont rather than six, using the single transferable vote system of proportional representation. The number of MLAs will fall to 90 from 108.
The decrease had been a long-standing DUP policy, but in the current climate of austerity all parties felt under pressure to accept that there should be fewer paid politicians.
The pain of the cut in seats is likely to be proportionately shared among the parties – Alliance is perhaps relatively least vulnerable providing it can maintain its vote share from last year.
Alliance should benefit because it will now be better placed to get transfers from trailing Nationalist candidates who are eliminated rather than ending as runners-up.
Smaller groups
The four biggest parties can all expect to lose between two to five seats.
The smaller groups (Greens and People Before Profit with two MLAs each, Traditional Unionist Voice with one, and the independent Claire Sugden) will also find it challenging to maintain their 2016 results.
The MLAs most at risk of losing their seats, in principle, will be those who came in sixth in each constituency last May. This list includes significant names – the SDLP's Alex Attwood in West Belfast; the speaker of the Assembly Robin Newton of the DUP in East Belfast; veteran campaigner Eamonn McCann in Foyle.
However, there could be exceptions, particularly in places where the unionist/nationalist divide is very close to 50/50 (Fermanagh and South Tyrone) or 67per cent/33 per cent (South Down, Newry and Armagh, Mid Ulster, East Londonderry, Upper Bann). There the fight for the last seat will come down to effective management of internal transfers within each community.
New constituency boundaries are currently being drawn up by the North's independent Boundary Commission, but they will not be available in time for a rapidly-called Assembly election.
Five seats
Once that review is finished, the Assembly in future years will be smaller again if the proposed new boundaries are ever implemented since they will take away another five seats, taking the total down to 85.
Northern Ireland remains relatively over-represented among the UK's devolved administrations; Wales, with almost twice the population, has only 40 members in its national assembly, and the Scottish parliament, representing three times Northern Ireland's population, has 129 MSPs, only a few more than Stormont's current 108.
Even without a boundary revision, the effect of the cut in seats on the style of any election campaign will be pretty vicious.
Each party knows that roughly a sixth of its MLAs are at risk. Parties which hold two, three or four seats in a constituency at present will have to select candidates carefully. In many cases fewer will be best, but it is very difficult to tell veteran figures that there may be no space on the ballot paper for them this year.
Parties in these circumstances tend to over-nominate, and let the voters sort it out. This is good for encouraging activity from party workers but very bad for party discipline, and gives incentives to candidates to fight among themselves for their base vote rather than reaching out to others.
Party loyalty
The members of a new Assembly may well have less internal cohesion and party loyalty than before, and will want to push their leaders to take a tougher line in the post-election negotiations.
Such an outcome could create yet another hurdle that must be surmounted if a deal is to be found between the leaders of nationalism and unionism for a return of devolved government.
Meanwhile, Northern Ireland will find its representation in the House of Commons falling by one from 18 under a plan to cut the number of MPs to 600 seats from the current 650.
The first attempt to legislate for a new map on those principles was killed off in 2013 by the Liberal Democrats, who were then in coalition with the Conservatives. The Liberal Democrats are now out of the picture, but any new cut will have to persuade a significant number of Conservatives to vote in favour of the abolition of their own seats.
Nicholas Whyte is a visiting professor in the faculty of social science, Ulster University, and a senior director in the Brussels office of APCO Worldwide