Nearly half of the respondents said independent candidate Ralph Nader should be included.

Barr, the former Republican congressman from Georgia who changed parties for this election, was favored by 55 percent of those taking the poll to be added to the debates. Nearly half -- 46 percent -- want Nader, who ran unsuccessfully the past two elections.

Among independents, 69 percent want Barr and 59 percent favor Nader appearing on the same stage as Sens. John McCain and Barack Obama, the poll indicates.

The first debate is scheduled Sept. 26 at the University of Mississippi in Oxford.

Zogby's interactive online survey, conducted Aug. 12-14, questioned 3,339 likely U.S. voters. It has a margin of error of plus or minus 1.7 percentage points.