Yes, it is the centre-right that did this. The left is not blameless, they nibbled on the edge of the structure last year when they broke out a tax reduction and stopped that with far-right support, but this is a big escalation.

If new elections return the same parliament it is up to the current speaker (soc-dem) to lead discussions and nominate a PM, or at least that is the case until a new speaker is elected. In September the speaker in the outgoing parliament (moderate, ie right-wing) demanded that Löfven showed that he had support to pass a budget, despite the former government voting collectively for theirs. In effect a deal with greens and left had to be shown before the speaker nominated him. The speaker's nomination is elected unless a majority votes against.

In tit-for-tat the outgoing speaker can demand the same thing of a centre-right government, and now the limit for being able to pass a budget has increased to majority, so centre-right + far-right. Or another new election. Or a break-up of the current bloc structure.

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