The distinctions concern in the first place their type of authorization. Contracts require the deliberation and approval of two-thirds of the senators present, but only executive agreements can be executed by the president alone. Some contracts give the President the power to fill in the gaps through executive agreements and not through additional contracts or protocols. Finally, agreements between Congress and the executive branch require a majority of the House of Representatives and the Senate before or after the president signed the treaty. The possibility of withdrawal depends on the terms of the contract and its preparatory work. For example, it was found that it was not possible to withdraw from the International Covenant on Civil and Political Rights. When North Korea announced its intention to do so, the UN Secretary-General, as registrar, said that the original signatories to the ICCPR had not neglected the possibility of explicitly withdrawing, but deliberately intended not to provide for it. Therefore, it was not possible to withdraw.  A contract is void and not abnormal if it is contrary to a peremptory norm. Unlike other principles of customary law, these norms are recognized as inadmissible and therefore cannot be modified by contractual obligations. These are limited to universally recognized prohibitions, such as the fight against the aggressive use of force, genocide and other crimes against humanity, piracy, hostilities against the civilian population, racial discrimination and apartheid, slavery and torture, which means that no state can legally assume an obligation to commit or authorize such acts. Bilateral agreements are concluded between two states or entities.  It is possible for a bilateral treaty to have more than two parties; Thus, each of the bilateral treaties between Switzerland and the European Union (EU) has seventeen parts: the parties are divided into two groups, the Swiss (“on the one hand”) and the EU and its member states (“on the other”). The Treaty establishes rights and obligations between Switzerland and the EU and the Member States in a single context – it does not create any rights or obligations between the EU and its Member States. [Citation required] In addition to treaties, there are other, less formal international agreements. These include efforts such as the Proliferation Security Initiative (PSI) and the G7 Global Partnership Against the Spread of Mass Destruction. Although the PSI has a “Declaration of Prohibition Principles” and the G7 Global Partnership, several G7 leaders` declarations, neither has a legally binding document, which sets out specific commitments and is signed or ratified by member states. World Treaty Index (Open Access) – contains metadata for nearly 75,000 contracts that came into effect in the twentieth century. Users can search for many access points, including citation; keyword of the title; the name of the party (including countries and organizations); subject; whether the treaty is bilateral or multilateral; and the date of signature. .