Evidence from 2010

Looking back is sometimes helpful, not least when talking about elections. Calling up Sweden 2010, there were two outspoken pre-electoral coalitions: the incumbent Centre-Right and a Socialist-Green alternative. There were a couple of parties somewhat at risk of falling below the threshold. Before the election, Prime Minister Fredrik Reinfeldt outspokenly encouraged voters to cast a strategic vote for the Centre-Right  to keep the upcoming xenophobic Sweden Democrats out of power. 

In the end, all seven parliamentary parties, and the Sweden Democrats, made it to the parliament and the Centre-Right government was elected to stay in office. Looking more closely at what happened, data from the 2010 Swedish National Election study shows that it would have been difficult for the Christian Democrats, included in the incumbent coalition, to make it if it weren't for strategic votes. When comparing voters’ first preferences in the pre-election study with their final vote choice, it appears that among those who voted for the Christian Democrats, a majority actually had the largest party in the coalition – the Moderate Party – as their most preferred party:

 First party preference and vote for Christian Democrats (KD)

Preference (%)
Left Party (V)	1,9
Social Democrats (S)	3,8
Centre Party (C)	18,9
People’s Party Liberals (FP)	13,2
Moderate Party (M)	50,9
Christian Democrats (KD)	49,1
Green Party (MP)	9,4
Sweden Democrats (SD)	0,0
n	53
percent KD votes	6,1
NOTE: Pre-election sample, voters who voted for other parties excluded. Preference(s) based on voters’ highest score on 11-point sympathy scale, including ties, (= possible to have two or more parties highest scored).

This indicates that voters had other reasons than sincere party preference to choose the Christian Democrats. Furthermore, when using a more specific measurement of "threshold incentives" (motives to vote for a party because it is in danger of not reaching the threshold to the parliament) and controlling for other factors important for vote choice, such as party identification and number of socio-economic variables, the chances to vote for the Christian Democrats increases by a quarter. These analyses also show that in this election it was the Christian Democrats and not so much the other small parties that benefited from strategic votes.

In the 2010 Swedish national election, motives related to the electoral threshold and considerations of government outcomes had a substantial impact in voting for the Christian Democrats. There was a movement from the other Centre-Right parties, in particular the Moderate Party, to this party. This year Sweden is approaching a new general election annd the coalition alternatives are not as set as last time.  This analysis of the previous election indicates that the Christian Democrats have a group of potential strategic votes. Still, no strategic votes can be taken for granted. 

For full paper and analysis of the 2010 Swedish General Election, see

http://www.tandfonline.com/eprint/uaZsqXEeRTphADEypayP/full

Journal of Elections, Public Opinion and Parties, published online