Amid tensions over Syria and Ukraine, President Obama and Russian leader Vladimir Putin will meet in New York during the United Nations General Assembly on September 28. The two leaders are at odds over what the U.S. calls Russian aggression in Syria and Ukraine. Alexis Simendinger of RealClearPolitics explains the challenges the two sides face trying to find common ground on their profound differences. The Washington Post's Dan Balz explains how a fickle GOP electorate may have lead to Wisconsin Gov. Scott Walker's surprise early exit from the 2016 presidential campaign.