Memorandum of understanding

A Memorandum of Understanding (MoU) is a legal document describing a bilateral or multilateral agreement between parties. It expresses a convergence of will between the parties, indicating an intended common line of action and may not imply a legal commitment. It is a more formal alternative to a gentlemen's agreement, but in some cases, depending on the exact wording, lacks the binding power of a contract.

In private law
In private U.S. law, MoU is a common synonym for a letter of intent (LoI). One example is the MoU between Bush and Kerry for the 2004 debates.

Inside a company or government agency
Many companies and government agencies use MoUs to define a relationship between departments, agencies or closely held companies. These branches of the organization fall under similar control structures but need to ensure smooth operations where there are shared resources or workflows. These could include areas such as Service Level Agreements (SLAs), intra-organization connectivity, intra-organization communications and intra-organization escalations and response patterns. Like the MoU in law, it creates a platform for a clear understanding of each party's commitments/purpose and sets out expectations for a series of pre-determined responses should certain criteria be met that shows that there is either intentional or unintentional breach of the MoU's original

In public international law
In international relations, MoU fall under the broad category of treaties. However, MoUs may in theory be kept confidential, although the United Nations Legal Section indicates that MoUs should be registered in the Treaty Database to avoid 'secret diplomacy'. One advantage of MoUs over more formal instruments is that they can be put into effect ("enter into force") in most countries without requiring parliamentary ratification. MoUs are often used to modify and adapt existing treaties. The decision concerning ratification, however, is determined by the parties' internal law and depends to a large degree on the subject agreed upon. Although MOUs in the multilateral field are seldomly seen, the transnational aviation agreements are actually MoUs.
Examples include:
The Memorandum of Understanding Relating to the Treaty between the United States of America and the Union of Soviet Socialist Republics on the Limitation of Anti-Ballistic Missile Systems on May 26, 1972 signed by US President Richard Nixon and the USSR Successor States updating the Anti-Ballistic Missile Treaty[1]
The Memorandum of Understanding on Hijacking of Aircraft and Vessels and Other Offenses between the US and Cuba, meant to criminalize hijacking in both countries (February 3, 1973)
The Agreed Framework between the U.S. and North Korea over nuclear weaponry on October 21, 1994
The Oil for Food program, for which Iraq signed an MoU in 1996
The agreement between the government of Indonesia and the GAM in the Aceh peace process, 15 August, 2005.