The 2008 US presidential race, which has already drawn a record number of dollars and voters, is poised to shatter another record: the amount of money spent on television advertisements.

As Democrat Barack Obama and Republican John McCain barnstorm across the country before the November election, they will spend heavily on ads that will increasingly reflect the cut-and-thrust of the campaign.

Total spending on TV ads in the presidential race is expected to top $800 million, said Evan Tracey, chief operating officer of the Campaign Media Analysis Group, which tracks political advertising. Such spending totaled $500 million, the previous record, in the 2004 race.