The first debate is set of a hotly contested Pennsylvania U.S. Senate race that could decide whether the GOP hangs onto its Senate majority.
Republican incumbent Pat Toomey will square off against Democratic challenger Katie McGinty today.
The hour-long debate will be taped at 1 p.m. at KDKA-TV in Pittsburgh and broadcast at 7 p.m.
It will be made available to stations in other media markets across the state.
Differences over national security, tax policy, gun rights, abortion and immigration are prominent issues in the race.