A major exception among the gubernatorial class eyeing 2016 is Bush. The former Florida governor has traveled across the country promoting Common Core and has called opposition to the standards “troubling.” Kasich also still supports the standards and chastised people who call them “ObamaCore.”

Ted Cruz of Texas, Marco Rubio of Florida and Paul of Kentucky, all senators considering White House runs, have spoken out against the standards, with Cruz and Paul promising to push for congressional action against them. Paul has declared that any supporter of Common Core “probably doesn’t have much chance of winning in a Republican primary.”

Even though the business community still backs Common Core, which grew out of a bipartisan National Governors Association initiative, Gallup has found surging opposition among GOP parents, up from 42 percent in April to 58 percent in October.

“It’s an issue that isn’t sexy enough for D.C. folks, but at the grass-roots level, it’s a very big deal and will be a measuring stick for all these guys,” conservative strategist Keith Appell said.