A constitution is the supreme law of any country. It provides the legal framework for the government, designates the powers and duties of the branches of government or governmental agencies, and establishes the relationship between the people and the government. It enunciates the basic rights and obligations of citizens, and usually establishes the basis for the country’s electoral system. The integrity of elections can be strengthened by entrenching the principle of universal suffrage in the constitution, setting the frequency of elections and specifying the basic eligibility criteria for  major elective offices and for citizens to register to vote. A constitution generally guarantees the basic political freedoms needed for competitive elections, such as freedom of speech, association, assembly, movement and expression (including the press).

It is important for the drafters of the constitution to take into consideration the capacity and conditions of the country. For example, an overly short interval between elections might be burdensome for less developed countries. The constitution normally determines the overall system for electing candidates to national offices. In the case of parliamentary elections, a basic decision is whether to adopt a proportional or a majoritarian system – viz., whether to elect candidates from lists submitted by political parties, with the winners to be determined by their party’s relative proportion of the vote; or of individual candidates who contest elections in geographical districts. 

A constitution may also authorize various institutions to undertake specific electoral or related functions. For example, it may establish an independent commission to administer elections, or assign specific electoral functions to standing government bodies.  It may also assign adjudicatory power over electoral disputes to the regular judicial system or a special court (such as a constitutional court or special electoral tribunal).