Ratification is a principal's approval of an act of its agent where the agent lacked authority to legally bind the principal. Ratification defines the international act whereby a state indicates its consent to be bound to a treaty if the parties intended to show their consent by such an act. In the case of bilateral treaties, ratification is usually accomplished by exchanging the requisite instruments, while in the case of multilateral treaties the usual procedure is for the depositary to collect the ratifications of all states, keeping all parties informed of the situation. The institution of ratification grants states the necessary time-frame to seek the required approval for the treaty on the domestic level and to enact the necessary legislation to give domestic effect to that treaty. The term applies to private contract law, international treaties, and constitutions in federations such as the United States and Canada. The term is also used in parliamentary procedure in deliberative assemblies.
In contract law, the need for ratification can arise in two ways: if the agent attempts to bind the principal despite lacking the authority to do so and if the principal authorizes the agent to make an agreement, but reserves the right to approve it. An example of the former situation is an employee not normally responsible for procuring supplies contracting to do so on the employer's behalf. The employer's choice on discovering the contract is to ratify it or to repudiate it.
The other situation is common in trade union collective bargaining agreements. The union authorizes one or more people to negotiate and sign an agreement with management. A collective bargaining agreement can not become legally binding until the union members ratify the agreement. If they do not approve it, the agreement is void, and negotiations resume.
The ratification of international treaties is always accomplished by filing instruments of ratification as provided for in the treaty. In most democracies, the legislature authorizes the government to ratify treaties through standard legislative procedures by passing a bill.