John Robert Bolton (born November 20, 1948) is an American lawyer and diplomat who served in various positions under Republican administrations.
A conservative, Bolton served as the United States Ambassador to the United Nations from August 2005 until December 2006 as a recess appointee by President George W. Bush. He resigned in December 2006, when the recess appointment would have otherwise ended, because he was unlikely to win confirmation from the Senate in which a newly elected Democratic Party majority would be taking control in January 2007. On March 22, 2018, President Donald Trump announced that Bolton would serve as his next National Security Advisor, and will take office on April 9, 2018. 
Under Secretary of State
Bolton led the George W. Bush administration’s opposition on constitutional grounds to the International Criminal Court, negotiating with many countries to sign agreements, called Article 98 agreements, with the U.S. to exempt Americans from prosecution by the court, which is not recognized by the U.S.; more than 100 countries have signed such agreements. Bolton said the decision to pull out of the ICC was the “happiest moment” of his political career to date.
Weapons of mass destruction
Bolton was instrumental in derailing a 2001 biological weapons conference in Geneva convened to endorse a UN proposal to enforce the 1972 Biological Weapons Convention. “U.S. officials, led by Bolton, argued that the plan would have put U.S. national security at risk by allowing spot inspections of suspected U.S. weapons sites, despite the fact that the U.S. claims not to have carried out any research for offensive purposes since 1969.”
Also in 2002, Bolton is said to have flown to Europe to demand the resignation of Jose Bustani, head of the Organization for the Prohibition of Chemical Weapons (OPCW), and to have orchestrated his removal at a special session of the organization. The United Nations’ highest administrative tribunal later condemned the action as an “unacceptable violation” of principles protecting international civil servants. Bustani had been unanimously re-elected for a four-year term—with strong U.S. support – in May 2000, and in 2001 was praised for his leadership by Colin Powell.
He also pushed for reduced funding for the Nunn-Lugar Cooperative Threat Reduction program to halt the proliferation of nuclear materials. At the same time, he was involved in the implementation of the Proliferation Security Initiative, working with a number of countries to intercept the trafficking in weapons of mass destruction and in materials for use in building nuclear weapons.