Sweden has bloc politics, i.e. no single party has the majority to govern.
The red-green bloc (left, center and greens) won a majority but the center party is playing kingmaker and refusing to let the left party into government. The left party has said from well before the election that they, reasonably, will not vote to support a government which they are not part of.
This has been due to decades of bourgeois / social democrat rat-fucking on policies, most notably disability / sick insurance reforms, after they got the left party's support votes. [1]
There is speculation that the center party would instead support the prior right wing government instead (voting with the extreme-right) - as long as the extreme right stays out of government, despite the extreme right getting all of their policies pushed through anyway. Even going so far as to withhold key votes in parliament until their immigration reforms (removing permanent residency and restricting citizenship, in this case) got passed. [2]
The short of it is that "centrist" parties are just right wing parties in disguise, in that they NEVER support leftist reforms but will happily support the right when it suits upper class economic interests.
Democracy being what it is, can be messy and nobody goes home happy. But the left of the left bloc saw the largest electoral gains in this election, so a move to the left is arguably what a growing portion of the electorate wanted. It was still a very close election, so you could frame it in many ways, but that the green-reds did see the biggest gains is fact.
1. https://arbetet.se/2026/09/21/sjukforsakringen-forklarar-var...
2. https://www.thelocal.se/20261012/beer-strike-and-contract-br...
