Finally, they have the debate stage to themselves: The philosopher-politician vs. the businessman-preacher.

Newt Gingrich, the onetime House speaker whose appeal is his endless buffet of ideas, and Herman Cain, the former restaurant executive whose appeal is his folksy simplicity, first locked arms in the mid-1990s over their mutual abhorrence of health-care reform and adoration of welfare reform. If any two Republican presidential hopefuls may be brothers from different mothers, as Cain referred to his relationship with the wealthy Koch brothers, they are Gingrich and Cain.

On Saturday night, the amiable duo will seek to unleash their intellectual and rhetorical firepower on a ballroom of tea party activists in this Houston suburb. They will square off in a 90-minute debate designed to signal a departure from the it’s-my-turn-to-speak gotcha slugfests that have dominated the GOP presidential debate circuit.