When Established Center Parties in Power Loose at Local Elections – Incumbency Bonuses in Decline, Polarization on the Rise, or Increasing Parliamentary Swings?

At the November 2025 Danish local elections, the usual competition between the three major political parties at the municipal level – Social Democrats, Conservatives, and Agrarian Liberals – finished somewhat inconclusively, since all three of them experienced a decrease in their electoral support. These local power parties lost votes to smaller parties, newer parties, and parties closer to the extreme end of the left-right continuum of Danish politics. The pundits’ first call has been that this is due to these parties being quite unpopular at the national level, where, not least, the grand coalition between Social Democrats, Moderates, and Agrarian Liberals in the national government has been criticized among party faithfuls. However, this explanation suppresses potential local electoral factors such as mayoral party bonuses, local front-runner candidates, and traditional local strongholds. By factoring in these factors, this paper will demonstrate to what degree the electoral result was a move away from the Center-Left and Center-Right parties cooperating at the national level towards more polarizing parties. Or if this was more a pattern of local-level mayoral bonuses turning into local cost of ruling effects due to the power parties’ inefficiency in circulating new mayoral candidates.