In this thesis the constitutional policies of the three Commoner Estates (Priests, Burghers and Peasants) of the Swedish Riksdag between the years 1660 and 1682 is examined. While many previous historians have focused on the power-struggle between the Crown and the nobility, the Commoner Estates have been presumed to be staunch supporters of absolutism. I argue that the picture is far more complex. Case-studies of a number of political negotiations that concerned the distribution of political power show that the Commoners were flexible in their constitutional policies. When they sensed they were in a strong position, they were explicit in their demand for a say in political decisions. But when they were weak, they were deferential to the government. If there is one constant in their policies it is not blind reverence to royalties: the thesis show that they could sacrifice the interests of powerless members of the royal family in favour of security and defence of Protestant faith. In comparison, the Commoners were more eager to protect the rights of their own Estates and of the Riksdag as a whole. One important feature of Commoner politics was the willingness of Priests, Burghers and Peasants to co-operate, which sometimes made them quite influential. In the thesis the relations between the Estates are examined. I also have endeavoured to examine the political institutions, the rules that governed politics in the Riksdag during the period. It is observed that the institutional structures were quite complex and unclear, which gav an advantage to well-oriented Estates like the Priests and the Nobility in comparison with the Peasants. The Priests also was the best organized Estate of the Commoners. Other factors that favoured the clergy was that they were led by politically experienced bishops; that they had common privileges that all priests were interested in defending; and that they were strengthened and united by their religious ideology.