Joe Biden's been indecisive about a presidential run. That indecision ended today. The former vice president became the 20th Democrat to declare. What's his pitch to a party with a diverse field to choose from? A surge in measles cases has led to extraordinary measures in New York City. The mayor declared a state of emergency this month. So why is the outbreak getting worse? And Russian president Vladimir Putin shook hands today with North Korean leader Kim Jong Un. They pledged to boost ties between the two nations. What implications do today's meetings hold for for U.S. diplomacy?