The debates are now the centrepiece of the presidential campaign.
The first encounter between Barack Obama and Mitt Romney drew 67m viewers,
making it the most widely watched debate in 20 years.
If 100m people do indeed watch tonight鈥檚 debate that would put it on a
level with the Super Bowl for viewing figures.聽
With the race so tight the pressure on the candidates is enormous; a slip-up
on live television could spell disaster for either campaign
