Coalition agreement and party mandate: How coalition agreements constrain the ministers

In coalition government, the relationship between parties and ministers is one of double delegation: from the party to the minister and from the coalition of parties to the individual minister. On the basis of principal—agent theory, I argue that a coalition agreement is a tool used by coalition parties to reduce agency loss when delegating to ministers. In six governments in Belgium, Italy and The Netherlands, I show that: a majority of the pledges were transferred into cabinet decisions, a majority of cabinet decisions were effectively constrained by the coalition agreement and that one-third of cabinet decisions had been precisely defined beforehand in the document. Interestingly, the length of the coalition agreement, the entry of party leaders to government and the number of ministers participating in the negotiations do not seem to have had a significant influence on the above two measurements.