Scrambling to salvage his presidential campaign, Joe Biden escalated his criticism of Pete Buttigieg on Saturday, mocking Buttigieg's experience as a small city mayor and cutting down the comparisons Buttigieg has drawn to the last Democratic president, declaring: "This guy's not a Barack Obama."

Pete Buttigieg and Joe Biden stepped up their criticisms of Bernie Sanders on Thursday, seeking to dull any momentum the progressive senator may gain heading into next week's Iowa caucuses.