This week’s show covers three key Senate races in the 2018 midterms – and covers them by sending correspondents there to test political temperatures at ground level. John Heilemann goes to North Dakota to interview Democratic Sen. Heidi Heitkamp (pictured); Alex Wagner interviews another Democrat, Nevada Representative Jacky Rosen, who’s running for the Senate opposite Republican incumbent Dean Heller; and Mark McKinnon travels to Arizona to cover both sides of one of the most competitive Senate races in this coming election, between Republican Representative Martha McSally and Democrat Representative Kyrsten Sinema.