Should we care who wins the ”median legislator” in Sweden?

Guest post by Nicholas Aylott

The term ”median legislator” is a staple of coalition studies (Laver and Schofield 1990). It connotes a decisive political position. Imagine the members of a parliament arranged on a single spectrum of opinion. The one right in the middle should thus decide all outcomes by choosing – presumably in return for something – to vote either with the forces to her left or to her right, thus creating a winning majority. If the vote is about which parties should be in government, this median legislator, or rather her party, should be so powerful that it can ensure its own place in that government, regardless of how many of its own votes it has. That party truly holds the balance of power.

Needless to say, real-world politics is vastly more complicated. Nevertheless, the median-legislator hypothesis does usually work in Sweden. Figure 1 shows the distribution of seats since the first election to a unicameral parliament. With only a couple of exceptions (circled), the party that straddles the median position after an election, denoted by the vertical line running down from the 50% mark on the horizontal axis, has indeed ended up in government.

Figure 1. Simplified distribution of seats in the Swedish parliament

Figure 1
Notes. For the sake of simplicity, the four parties that constitute the Alliance, which was formed in 2004, are combined. Parties that formed the government after an election are denoted with the bars solidly filled; opposition parties are shown with patterned fill. Governments formed in the middle of parliamentary terms are excluded.  Data were adapted from Bergman (undated).

Why does the hypothesis tend to work in Sweden? One big reason is that the country’s politics really is dominated by the left-to-right dimension, perhaps to a greater degree than in any other European country. The Greens, it is true, are harder to place in left-to-right terms. Still, most observers of contemporary Swedish politics, plus the Swedish Parliamentary Surveys conducted by political scientists at the University of Gothenburg (thanks to Peter Esaiasson and Lena Wängnerud for help with access to these data), put them to the Social Democrats’ right, as in Figure 1. If so, the Greens have won the median position on two occasions, in 1998 and 2002.

However, as Figure 1 shows, those were the occasions on which the median-legislator hypothesis did not work. Instead of getting into government, the Greens were fobbed off by the Social Democrats with parliamentary ”contracts”, in which the Greens got policy promises and even junior ministerial jobs, but not cabinet portfolios (Bale and Bergman 2006). The second such episode, in 2002, was particularly interesting, because the Greens, prior to the election, had made explicit promises about voting against any government from which they were excluded. After the election, they had also negotiated for a while with three of the centre-right parties about a coalition that, had it been realised, certainly would have included the Greens – and would thus have confirmed the median-legislator hypothesis.

Why did the Greens, despite their ostensibly decisive parliamentary position, settle for less than the place in a full executive coalition that they had demanded? A few years ago, Tobjörn Bergman and I investigated this ”puzzle of government formation” (Aylott and Bergman 2011). Our argument was that two factors interacted to explain the deviant case.

The most important factor was intra-party constraints on the Greens’ leadership. The party’s membership had drifted sufficiently far to the left in the years before the 2002 election, and the party’s organisation and culture were sufficiently flat and democratic, to dissuade the leadership from actively facilitating a non-left government.

Second, the party leadership was further constrained by the institutional context. As is well known, ”negative parliamentarism” applies (Bergman 1993; Bergman 2014; Davidsson 2014). To survive, a government need only avoid the formal expression of an absolute parliamentary majority of no confidence in it. The least difficult post-election option for the Greens in 2002 was to abstain when the centre-right brought a vote of no-confidence in the incumbent Social Democratic government – and that was thus enough to preclude any absolute majority when the vote came.

Does that mean that we shouldn’t care about which party ends up holding the median legislator after the coming election? Not at all. Any outcome will be interesting from a political-science perspective.

One possibility is that the median position will be reconquered by the Greens – which, this time, would surely see them proceed into a first full government coalition. The Social Democrats, for their part, have recognised the difficulty of governing alone, given their electoral decline over the last dozen years, and have more or less designated the Greens as preferred coalition partners – a very different attitude to the one the Social Democrats had in 2002.

If this scenario were realised, it would mean that the left-of-centre parties, including the Greens, had won a parliamentary majority. Unfortunately for them, that currently looks rather unlikely. And unfortunately for the currently governing Alliance parties, they will probably finish even further from a majority. The reason, of course, is the looming presence of the Sweden Democrats on the far right, where they are conventionally placed. That presence may put the Swedish party system under great strain.

The Alliance has pledged to give the Social Democrats first go at forming a government if, as looks certain, their combined score is smaller than that of the left-of-centre parties (Reinfeldt et al 2014). Yet the toughest decisions will probably face the left-most Alliance party, the likeliest holder of the median legislator. That party is probably the Liberals.

With the median position, they would have extraordinary influence. They could pursue a deal with the Sweden Democrats, thus cementing a right-of-centre majority (and, indeed, the left-to-right character of Swedish party competition). But that seems inconceivable, such is the cordon sanitaire around the far right. Alternatively, the Liberals could seek to tempt the Greens into a deal with the Alliance. But the Greens’ leaders would find that a very hard sell to their members – much as their predecessors anticipated in 2002.

Or the Liberals could bite the bullet and do some deal with the Social Democrats.  A new semi-coalition contract, rather than a full coalition with the left, might make the arrangement slightly more palatable. Still, the intra-party constraints would be very considerable. The justification would be in ”saving” the country from the malevolent influence of the Sweden Democrats. Maybe that would enhance the reputation of the Liberals’ leaders; maybe, in time, that reputation might bring electoral rewards. But would members and sympathisers understand the need for such a brazen defection from the Alliance after a decade of commitment to it? Could the incumbent Liberal leader really pull off such a feat of political acrobatics? Might the prize of the median legislator turn out to be a poisoned chalice for him and his party?

Nicholas Aylott is associate professor of political science at Södetörn University and research leader in the Centre for Baltic and East European Studies.


Aylott, Nicholas and Torbjörn Bergman (2011), ”When Median-Legislator Theory Fails: Why the Swedish Greens Allowed Themselves to be Kept Out of Power in 1998 and 2002”, in Rudy W. Andeweg and Lieven De Winter (eds), Puzzles of Government Formation: Coalition Theory and Deviant Cases (London: Routledge).

Bale, Tim and Torbjörn Bergman (2006), ”Captives No Longer, but Servants Still? Contract Parliamentarism and the New Minority Governance in Sweden and New Zealand”, Government and Opposition 41, 422–449.

Bergman, Torbjörn (1993), ”Constitutional Design and Government Formation: The Expected Consequences of Negative Parliamentarism”, Scandinavian Political Studies 16, 285-304.

Bergman, Torbjörn (2014), ”What a difference a vote makes?”, Om makt och politik August 18 (

Bergman, Torbjörn (undated), European Representative Democracy Data Archive (

Davidsson, Lars (2014), ”Hur negativ är den svenska parlamentarismen? Överlevnadsstrategier i riksdagen efter 2014 års val”, Politologerna August 19 (

Laver, Michael and Norman Schofield (1990), Multiparty Government: The Politics of Coalition in Europe (Oxford: Oxford University Press).

Reinfeldt, Fredrik, Jan Björklund, Annie Lööf and Göran Högglund (2014), ”Vi godtar inte en regering som saknar stöd för budgeten”, Dagens Nyheter August 21.