In June, the Georgia Republican Party voted unanimously to oppose Common Core, the proposal to establish a uniform set of educational bench marks among the states. The agreement, Republicans said, “obliterates Georgia’s constitutional autonomy.” On Wednesday, Georgia Gov. Nathan Deal (R) ordered a review of the guidelines and asked the state board of education to “formally un-adopt” a part of the program. A Republican candidate running against Deal and courting tea party backers says it would have taken him “three seconds to reject Common Core in its entirety,” according to the Atlanta Journal-Constitution.

The opposition in Georgia has raised eyebrows because it was Deal’s predecessor, fellow Republican Sonny Perdue, who helped develop the Common Core principles in the first place.

Conservatives from Georgia and Alabama to Michigan and Indiana have lambasted the Common Core proposal as an intrusive mandate from the federal government. Indiana Gov. Mike Pence (R) withdrew his state from Common Core’s governing board earlier this month. Michigan’s Republican-controlled legislature will hold hearings skeptical of Common Core. And a local Alabama Republican Party publicly condemned the Alabama legislature and its local member of the state school board for failing to nix Common Core standards.

Both President Obama and Education Secretary Arne Duncan are strongly supportive of the standards, but it’s not their own: It grew out of a National Governors Association panel co-chaired by Perdue, whom no one could accuse of being a liberal, and Delaware Gov. Jack Markell, a Democrat.

“In the National Governors Association, we had been looking at what was happening internationally, and the bench marks they were using internationally, and where our students across the United States were falling. I guess that’s a double-edged word there, ‘falling,'” Perdue said in an interview. “It’s as if we in the United States were like Garrison Keillor in Lake Wobegon: We just thought all our kids were above average, and the stats didn’t support that.”

“We understood that, as a nation, our students were falling behind internationally, and in a globally competitive environment, we felt as governors, it was our job to have a world-class education for our students.”

Common Core aims to set uniform bench marks for educational attainment for elementary and high school students, Perdue said. Instead of imposing a common curriculum, it sets “common proficiency targets.” The federal government has a long history of meddling in state education policies, Perdue said, and imposing an agreement between states — led by Republican and Democratic governors alike — would be a way to avoid future national mandates.

“We felt like we needed to take steps as governors to actually prevent a federal mandate that came in this area. We saw No Child Left Behind as somewhat of an intrusion in state business,” Perdue said. “We didn’t want another federal mandate that came in and said, ‘Here’s what your state looks like compared to Switzerland,’ or wherever.”

“We felt something had to be done, and while the No Child Left Behind law was kind of a call to arms on accountability, it left every state to its own yardstick.”

Markell said Common Core standards would be particularly valuable to military families that move frequently from base to base.

“If you think about this from a perspective of a military family, they move every 18 months. What’s taught in fourth grade in one state could be taught in fifth grade in another. It’s ridiculous — think how hard it is for them to have any kind of continuity in their education,” Markell said.

Perdue said he was particularly influenced by “Tough Choices or Tough Times,” a report [pdf] by the National Center on Education and the Economy’s New Commission on the Skills of the American Workforce. That report, issued in 2010, found American students falling behind their international counterparts in advanced industrial nations in math, science and general literacy. (The commission included members as diverse as Rod Paige, George W. Bush’s secretary of education; John Engler, the former Republican governor of Michigan; Bill Brock, the former Republican senator from Tennessee; Joel Klein, then the New York City public schools chancellor; and Marc Morial, the president of the National Urban League.)

Perdue said he was deeply frustrated by the assumptions that Common Core comes from the federal government. “What concerns me most about this is that the paranoia has developed into innuendo and rumors that are not based on fact,” he said. “Our strength [as conservatives] comes from being informed and factual.”

“We all said we want an educated society and an educated state, but it’s incumbent upon us to define what an education is,” Perdue said. “You can’t miss these marks in first, third, fifth, eighth grade and come out with a brilliant college student.”