When citizens disagree with the decision of Parliament and they gather 50,000 valid signatures within 100 days of the official publication of the act, or eight cantons submit a request, the act is submitted to a vote of the People (an ). The act only comes into force if it is accepted by the majority of the People.
How to launch an optional referendum at federal level
Certain laws passed by Parliament, including amendments to the Federal Constitution, must be put a the vote of the People and the cantons. Amendments to the Federal Constitution only come into force if they are accepted by a majority of the People and the cantons.
Art. 140 of the Federal Constitution – Legislation put to the vote (mandatory referendum)