Republicans and Democrats in Nevada, North Dakota and South Carolina select their nominees on Tuesday, but much of the nation's political focus will be on Maine. Democrat Graham Platner is expected to emerge from the primary to take on five-term incumbent GOP Sen. Susan Collins. But Platner has faced one scandal after another during the campaign. Geoff Bennett discussed more with Alex Seitz-Wald.

NPR's Tamara Keith and Amy Walter of the Cook Political Report with Amy Walter join Amna Nawaz to discuss the latest political news, including Trump walking out under tough questioning on NBC's "Meet the Press," Democrats facing character questions ahead of a battleground Senate race, and the president's influence on the ballot in South Carolina.