Independents are split: Romney and Paul lead among that group by three points, Perry by two, but Obama leads Bachmann among independents by six points.
But there is likely to be a great deal of change between now and Election Day, according to a brief history of Gallup surveys conducted at this stage of the campaign.
-- In August 1999, then-Texas Gov. George W. Bush led Vice President Al Gore by 14 points. Gore ended up narrowly winning the popular vote.
-- In August 1995, then-Senate Majority Leader Robert Dole, R-Kan., had a two-point lead over President Bill Clinton. Dole lost by eight.
-- In August 1983, Ronald Reagan had a slender, one-point lead over former Vice President Walter Mondale. Reagan would be re-elected by 18 points the following November, after economic growth spiked in the second half of Reagan's first term.
-- In August 1979, President Jimmy Carter and Reagan were tied at 45 percent. Reagan won by 10 points in 1980.
The new Gallup poll was conducted Aug. 17-18. Gallup surveyed 879 registered voters, for a margin of error of +/- 3.3 percent.