VIDEO : Trump Names John Bolton As National Security Adviser

According to President Donald Trump on Twitter, John Bolton, the former U.S. ambassador to the United Nations, will replace H.R. McMaster as national security adviser. Bolton served in the George W. Bush administration. He is known for his hard-line foreign policy views, and supports attacking North Korea. Bolton will become the administration's third national security adviser in just over a year. He will join the White House as Trump approaches a very high stakes period of his presidency.