Legal provisions for optional referendums at national level

Constitution of Uruguay (Constitución dela República Oriental del Uruguay),

http://www.refworld.org/docid/3ae6b5600.html

Article 79.

The accumulation of votes for any electedoffice, with the exception of those for President and Vice President, shall beeffected through use of the slogan of the political party. The Law, by atwo-thirds vote of the full membership of each Chamber, shall establish rulesfor this requirement.

Twenty-five percent of all persons registeredand qualified to vote may, within one year following their promulgation, demanda referendum against the laws and exercise the right of initiative before theLegislative Power. These institutions are not applicable with respect to lawsimposing taxes. They are likewise inapplicable in those cases in which theinitiative is an exclusive right of the Executive Power. Both institutionsshall be regulated by law, enacted by an absolute majority of the fullmembership of each Chamber.