A constitution is the supreme law of any nation. It provides the framework of government, designates the powers and duties of the branches of government or governmental agencies and establishes the relationship between the people and their government. It details the basic rights and obligations of its citizens and usually provides the framework for the nation's electoral system.

For election integrity purposes, the constitution can ensure universal suffrage, set the frequency of elections and the basic eligibility requirements for the major elected offices. In doing so, the drafters of the constitution should take into consideration the capacity and conditions of the country. For example, setting elections at too close an interval can be burdensome for some less developed countries. In countries coming out of conflict, a proportional system might allow for more power-sharing than a winner-take-all system.

Constitutions can also ensure the basic political freedoms needed to hold competitive elections, such as freedom of speech, assembly, movement and press. It can also enable political actors to form into groups for the purpose of contesting office or to support group interests.

Constitutions may also authorize institutions to undertake specific electoral functions. For example, it may give election administrative power to a government institution or an independent commission; and enforcement powers and responsibilities to the judicial system or a specific electoral court.