Efter at Fællesakten trådte i kraft i 1987,harde store grupper måttet samarbejde, for Parla­mentet kan kun gøre effektiv brug af sin medbestemmelsesret, hvis det er det absolutte flertal på 260 stemmer, der taler.
Cooperation between the major parliamentary groups has been necessary since the Single European Act (which came into force in 1987), for only with an absolute majority of 260 votes can Parliament make effective use of its power of co­decision.