Democrats across the U.S. are showing a strong desire for change. And in Massachusetts, U.S. Rep. Seth Moulton hopes this momentum will help him unseat longtime Sen. Ed Markey in the Democratic primary. Moulton is a moderate who has argued that a generational change is needed and questioned Markey's accomplishments. The 80-year-old Markey countered that Moulton is out of touch with the state's voters. The primary is crucial in heavily Democratic Massachusetts, and the winner will be expected to prevail in November's general election. Candidates for the House on Tuesday's ballot are also challenging older incumbents.