After Trump and Carson, there is a significant falloff in support for the other candidates. Former Florida governor Jeb Bush, who began the year as the nominal GOP front-runner, stands at 8 percent, his lowest ever in Post-ABC surveys of the 2016 field. Next, at 7 percent each, are Sens. Ted Cruz of Texas and Marco Rubio of Florida. No one else registered above 5 percent.

Sen. Rand Paul of Kentucky, former Arkansas governor Mike Huckabee, Wisconsin Gov. Scott Walker and New Jersey Gov. Chris Christie either tied or registered their lowest levels of support in Post-ABC polls of the 2016 race dating to the beginning of 2014.

Walker suffered the steepest decline since the July survey, falling from 13 percent to 2 percent. Recent polls in Iowa, where Walker had been leading, also have shown a loss of support.