In the previous Winthrop poll, conducted in April, former Arkansas Gov. Mike Huckabee led the GOP field, with Romney trailing close behind. Perry was not included in the April poll. The Winthrop poll was conducted Sept. 11-18, surveying 596 registered Republicans and Republican-leaning independents, for a margin of error of +/- 4.0 percent. For the subsample of definite GOP primary voters, the margin of error is +/- 4.6 percent.