WASHINGTON – Finally, the fall season offers the matchup sure to attract the biggest audience of the campaign: President Barack Obama going one-on-one with Republican Mitt Romney in three prime-time debates.

Typically the top political draw in the final sprint to Election Day, the debates assume outsized importance this year with the race a dead heat.

The candidates will have their sound bites and rhetoric down cold so any slip or inadvertent move – remember President George H.W. Bush’s exasperated glance at his watch or Democrat Al Gore’s repeated sighing? – could roil the campaign for days and linger in voters’ minds until Nov. 6.