Viewers’ guide: Substance vs. personalities as stakes grow

MILWAUKEE (AP) — Organizers are promising to focus on substance when eight Republicans face off on the main stage for the GOP's fourth presidential debate.
While that's the plan, big personalities and rising tensions in the unsettled 2016 field could make for an unpredictable Tuesday evening in Milwaukee. Donald Trump and Ben Carson are fighting to maintain their place atop the polls, while others — including Jeb Bush — are fighting for their political survival in the 9 p.m. EST event.