And that’s the risk with Cruz. Tillis can try to leverage the support of Rubio or Paul to appeal to his state’s diverse electorate, but Cruz’s damn-the-torpedoes style—a proven winner for motivating the base—tends to narrow the playbook.

Consider what happened last Saturday in Georgia, as Cruz campaigned for Republican Senate nominee David Perdue. At New Life Church, an evangelical ministry in Canton, about an hour north of Atlanta, Cruz was in his element. Seated in the front row was Michael Baum, a 40-year-old hospital auditor who opposes gay marriage and, contrary to public polls, believes that most Americans do, too. Not far away was Bob Schmeidt, a 59-year-old consultant who created “Ted Cruz for President” stickers for the day and praised Cruz’s lead role in the federal government shutdown, calling it a belt-tightening measure.

Retiree Sarah Steingraber said she doesn’t think Obama cares about the country. Conrad Quagliaroli, wearing a “no socialists” pin, said Obama is the worst president in U.S. history—”but it’s not because he’s black.” Obama’s pandering to Hispanic voters has contributed to a porous southern border where Islamic State terrorists are now sneaking through, said Kathryn Garland, 60, though there’s no evidence of that.