The Social Democrats are proposing mandatory preschool from the age of 3. They believe it would benefit children's development in the Swedish language, especially in disadvantaged areas where children struggle to learn Swedish when it's not spoken at home.
Additionally, the Social Democrats think it would make it easier for parents to start working when their children are in preschool. This is part of the Social Democrats' effort to promote integration through improved Swedish language skills and to get more unemployed adults back to work.
The Moderates, on the other hand, are advocating for a preschool language school instead of mandatory preschool from the age of 3. This would involve teaching Swedish to children who don't speak the language well enough.
This was discussed in a debate on SR.
Universal preschool is currently offered, with at least 525 hours of free preschool per year for all children from the age of 3. This is available to all children residing in Sweden, including asylum seekers. However, there is no mandatory preschool attendance at present. [1]