Article 53 of the constitution provides that at least a majority of its members must be present in order for the Chamber to make decisions. It is noteworthy that this does not apply to all business of the Chamber, such as debates or questions to members of the federal government, but that a quorum must only be present in order to make decisions. If not enough members are present, the decision is invalid. In order to make a decision, at least 50% plus 1 of the members present and voting must vote in the affirmative. If a vote is tied, the president does not have a casting vote and the proposal is rejected. The procedure outlined in Article 53 of the constitution applies to all most decisions, however, the constitution establishes two exceptions: to amend the constitution, a two-thirds majority of the members must be present and at least two-thirds of the votes cast must be in the affirmative, and in order to adopt a so-called special law, a qualified majority of 50% plus 1 of each language group must be present and at least 50% plus 1 must be present and at least 50% plus 1 of the votes cast in each language group, as well as two-thirds of the votes cast of the two language groups together, must be in the affirmative.