What's on the table at the North Korea summit? CBS News senior global affairs contributor Ian Bremmer, president of the Eurasia Group, joins "CBS This Morning" to discuss the highly anticipated meeting between President Trump and North Korean dictator Kim Jong Un on Tuesday. He also explains why he thinks Mr. Trump's actions at the G7 summit is a geopolitical equivalent to his firing of former FBI Director James Comey, and how Mr. Trump has caused "grave damage" to relations with Canada.