Bulgaria - 1991 Constitution

Title Article 12
Chapter 1 - Fundamental Principles
Article

12

(2) Citizens’ associations, including trade unions, shall not pursue any political objectives, nor shall they involve in any political activity which is in the domain of the political parties.

Categories - Activity and behaviour (Democracy)
Source Gisbert H. Flanz ed. 2004. Constitutions of the Countries of the World. Dobbs Ferry, New York: Oceana Publications.