">UN General Assembly requires a two-thirds vote for “recommendations with respect to the maintenance of international peace and security”, including imposition of international sanctions. (For the full rules of procedure, click here.)
Of the 193 member nations, only five that sit on the Security Council are permanent members, or the P5s. They are China, France, Russia, United Kingdom, and United States. These five states, and only these, can veto a proposed resolution. If any P5 exercises this veto power, the resolution cannot pass. Over the years, this has has received wide criticism. Much of the criticism has been directed at Russia, the P5 that most frequently uses its veto power. Russia has blocked sanctions against Syria, the regime of Bashar al-Assad, four times and also against Ukraine, where Russia is party to the conflict.
">UN after World War II. The United States and Russia (then the Soviet Union) as the victors of the war, along with the United Kingdom, shaped the postwar political environment. US Pres. Franklin D. Roosevelt insisted on China's inclusion as a P5 state. Roosevelt envisioned international security presided over by "four global policemen."
">UN Charter, the Security Council may take assertive action, including the imposition of sanctions or the use of force "to maintain or restore international peace and security." Throughout its history, this has taken the form of peacekeeping missions.