John Bolton, the national security adviser, was ousted after fundamental disputes with President Trump over how to handle foreign policy challenges like Afghanistan, Iran and North Korea. But the two men disagreed about how they parted ways. Guest: Peter Baker, the chief White House correspondent for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.  Background reading:President Trump said he fired John Bolton; Mr. Bolton insisted that he had resigned. Regardless, they had a fundamental disagreement over foreign policy, most recently Afghanistan.Mr. Trump is now looking for the fourth national security adviser of his presidency. Here is a short list of possibilities.