Freedom of expression is not an absolute right and it may be limited in certain circumstances. But such limitations must conform to clearly defined standards. Almost invariably it will not be legitimate to restrict political speech before it is spoken. So, while a person who is defamed may have a legal remedy, it is not acceptable to apply prior censorship to politicians’ words to ensure that they do not contain defamatory content.

Article 19 of the International Covenant on Civil and Political Rights provides in paragraph 3 a number of grounds on which the right may be restricted.

The exercise of the rights provided for in paragraph 2 of this article carries with it special duties and responsibilities. It may therefore be subject to certain restrictions, but these shall only be such as are provided by law and are necessary: (a) For respect of the rights and reputations of others; (b) For the protection of national security or of public order, or of public health or morals.

Article 20 of the ICCPR may also be relevant on occasions. This prohibits propaganda for war and advocacy of national, racial or religious hatred that constitutes incitement to discrimination, hostility or violence.

The UN Technical Team on the Malawi Referendum applied these principles to national law governing a poll campaign. It stated that an restriction on freedom of expression:

should not be so vague or broadly defined as to leave an overly wide margin of discretion to the authorities responsible for enforcing the law, since uncertainty over legal boundaries has a dampening effect on the exercise of this right [to freedom of expression] and may encourage discrimination in ... [the restrictions'] application.[i]