For Democrats, there are already plenty of signs pointing to a good election night this November. There's the record number of House candidates outraising their Republican incumbent rivals. There's the unlikely rise of Texas senate candidate Beto O'Rourke giving Ted Cruz a real run for his seat. There are the upset victories in state legislature races, like the one in Virginia last fall. And of course, there are polls showing Democrats with a steady lead over Republicans on a generic ballot.