DENVER (AP) — The national political spotlight is again on Denver as President Barack Obama and Republican Mitt Romney meet in their first debate.

Romney has been in Colorado since Monday. The president arrives Wednesday afternoon.

Drivers are being warned that Interstate 25 through much of southern Denver will be closed for five hours because of the debate at the University of Denver. The closure has commuters scrambling for alternate routes or mass transit, with many deciding to work from home or call in sick.

The university expects protesters and interested observers to gather outside the debate. The debate will be shown on screens in the "DebateFest" area for people who didn't get tickets.

Watch parties are also planned around the state.