Why the D66 trumped GL–PvdA Strategic voting In the 2023 elections, the GL–PvdA alliance finished sec­ond largely because it was perceived as the main chal­lenger to the PVV and the VVD. Around half of its total 15.8% of voters supported the alliance for strategic rea­sons, hoping it would become the largest party and thus lead coalition negotiations, or at least be indispensable to a broad mainstream coalition. 5 Many of these strategic voters also viewed D66 as an acceptable alternative. As a result, GL–PvdA’s strong reliance on strategic voting in 2023 made it particularly vulnerable to the emergence of another progressive party as principal challenger to the PVV in 2025. This possibility did indeed materialise early in the 2025 ­campaign, when D66 quickly assumed the role of main challenger. From the outset of the campaign in September, party leader Rob Jetten dominated media coverage. His ­visibility was boosted, somewhat improbably, by a winning streak on the popular television quiz show The Smartest ­Human, starting on 11 September, but other factors included an attack on the D66 party headquarters by far-right activists on 20 September and his unexpected participation in a high-­profile televised debate on 12 October after Wilders withdrew for security reasons. 6 Leadership popularity Jetten’s media exposure boosted his popularity. His fa­vourability ratings rose and his social media following surged to 423,000 within two weeks, approaching that of Frans Timmermans. 7 Crucially, Jetten was also more pop­ular among prospective GL–PvdA voters than Timmer­mans himself, who recorded the lowest score of all party leaders among their own supporters. Preliminary data from the Dutch Parliamentary Election Study(DPES) indi­cate that GL–PvdA voters registering low approval of Tim­mermans and high evaluations of Jetten were particularly likely to defect to D66. Leadership thus played a decisive role in the 2025 elections, reinforced by strategic consider­ations. As D66 surged in the polls, it appeared increasing­ly likely to enter government, whereas the VVD consist­ently ruled out governing with GL–PvdA, portraying the alliance as too radical. Campaign framing Jetten also benefited from a campaign approach based on optimism and momentum. Drawing on elements associated with Obama-style campaigning, D66 emphasised hope, pos­itivity and a»can-do« ethos rather than making detailed pol­icy proposals. The party deliberately downplayed traditional issues such as climate change, which were still strongly ­associated with GroenLinks, and instead promoted a form of»progressive patriotism«. This combined a more centrist, and in some respects even centre-right, stance on immi­gration with strongly pro-European positions. D66 ac­knowledged the influx of asylum seekers as a societal problem requiring firm solutions, endorsed a Canadian-style immigration model and advocated the externalisation of asylum procedures outside the EU. Symbolically, Dutch and EU flags were displayed side by side at party rallies. This strategy proved effective in attracting even voters who had supported(far-)right parties in 2023, while Jetten also pre­sented himself as the principal opponent of Wilders, prom­ising to end the»Wilders era« and calling on democratic parties to unite behind him. This dual message resonated with both centrist and progressive voters. By contrast, GL–PvdA struggled to run a campaign that could be equally compelling. Although the alliance adopt­ed an economically left-wing and culturally progressive platform, it got in line with the broad rightward shift on immigration, setting migration targets and proposing re­strictions on labour migration. 8 Its campaign emphasised housing and health care, but lacked a clear long-term vi­sion. Furthermore, Timmermans often addressed these is­sues in a technocratic way. More generally, the campaign appeared unfocused and backward-looking, stressing the preservation of past achievements rather than putting ­forward a persuasive vision for the future. Taken together, the lack of leadership appeal and the framing of the cam­paign contributed significantly to GL–PvdA’s electoral losses in 2025. Going forward Despite GL-PvdA’s severe setback in 2025, especially given that the central aim of the ongoing merger was to consoli­date its position as the main challenger to the(far-)right, all is not lost for the alliance. Timmermans has been re­placed by Jesse Klaver, former leader of GroenLinks. Klaver is a significantly younger leader with extensive experience heading a more movement-oriented party and confronting the(far-)right from the opposition benches. He is widely re­garded as a strong debater and known for his ideological flexibility. Moreover, a minority coalition of D66, CDA and VVD has now formed on the basis of a clearly right-leaning coali­tion agreement. The agreement contains measures that would weaken social security, impose restrictive migra­tion policies and constitute a more modest approach to climate change, reflecting the strong influence of the VVD 9 on the agreement. GL-PvdA has made it clear that it cannot support these policies, however, and that the coalition would need to change course substantially be­fore the alliance considered backing the minority cabinet. Given the agreement’s rightward orientation overall, a firm oppositional strategy may prove more effective in the coming years than issue-­by-issue negotiations over conditional support. The 2025 Dutch elections 4