Another, Louisiana, is locked in a battle between tea party-backed Gov. Bobby Jindal, who's trying to scrap the standards he once supported, and his Education Department, which says he can't legally do that.
"What was originally thought of as an organic, state-led initiative became something with a federal heavy hand associated with it," said Michael McShane, a research fellow in education policy at the right-leaning American Enterprise Institute.
Developed by the National Governors Association and Council of Chief State School Officers in concert with teachers and education experts, the standards were envisioned as a key step toward boosting American competitiveness after years of decline in education.
In the last year, though, grassroots opposition has been brewing among conservatives who point to grants and waivers linked to the Common Core as a sign of a federal takeover of education. Conservative commentator Glenn Beck took to movie theaters Tuesday in a "national night of action," offering tips on how to fight the standards.
A year ago, Christie, who has tied teacher tenure to performance and crusaded against failing schools, blasted Republicans in Congress for opposing Common Core partly as a "kneejerk reaction" to President Obama's support of the standards.
In contrast with politicians in Washington, many of whom "care more about their primaries than they care about anything else," Christie declared at an education summit in Las Vegas that Republican governors like himself, as well as some Democrats, were "leading the change" on Common Core and "dragging Washington to the change."
On July 14, however, Christie slowed down Common Core rollout in New Jersey, creating a commission that will review tests aligned with the standards and examine their impact on school districts. As part of a compromise with the Legislature, the administration said that for two years, it would reduce the weight assigned to the new tests in teacher evaluations.
The commission, which will report to Christie in one year, will have to grapple with several factions. Teachers' unions support the standards but say the tests are unproven. Conservative and tea-party groups demand local control of schools, while the New Jersey Chamber of Commerce, like other business groups nationally, argues the standards will build a better workforce.
Christie's issuing an executive order to study Common Core "is a way of hedging his bets, trying to temper his acceptance of it," said Brigid Harrison, a professor of political science and law at Montclair State University.
Asked July 16 at a hedge fund conference in New York about his support for Common Core, the governor didn't directly answer but said: "What I support is to try to change something that's much more important than Common Core." Using teacher tenure as an example, he said, "we have an education system that puts the comfort of adults ahead of the comfort of children."
Reached for comment last week, Christie's office pointed to his executive order but declined to respond to questions about the governor's position.
Democratic legislators, buffeted by New Jersey's largest teachers' union, were pushing for a two-year moratorium on using the standards but were satisfied with Christie's commission. Some conservative policy analysts concerned that Beck's theatrics won't contribute to an important debate say there is room to improve Common Core, and New Jersey's review may do just that.
Nevertheless, Christie's delay might not be enough for conservative voters, many of whom are already suspicious of the blue-state Northeastern Republican.
The week before Christie established the commission, conservative activist Phyllis Schlafly wrote a commentary suggesting the governor faced "a dilemma that may determine whether he is a viable presidential candidate."
"Does he stand up for local control over education by stopping Common Core, as Jindal has done in Louisiana, or does Christie try to play both sides of the issue?" she asked.
Much like President George W. Bush's No Child Left Behind education law, which initially received broad bipartisan support but was later criticized as ineffective, Common Core wasn't always this controversial.
It sets academic goals but does not establish curriculum or tell states and teachers how to reach those goals. The Obama administration is funding two groups developing tests aligned to the standards, but some states have opted out of those tests, choosing to develop their own.
Common Core isn't required, but critics say eligibility requirements for federal grants and waivers closely align with the standards.
The backlash has been severe, and some critics have dubbed the standards "Obamacore," a riff on the Affordable Care Act, which is widely reviled by Republicans.
"It became real, just like Obamacare is becoming real, and people are flipping out about it," said Rick Shaftan, a former adviser to Steve Lonegan, the tea-party favorite who ran for Congress this year and U.S. Senate in 2013.
On Thursday at a forum of Republican governors at the Aspen Institute in Colorado, South Carolina Gov. Nikki Haley said her state was opting out of Common Core because "whether it's health care, whether it's regulations, whether it's education, everything should be state-run." Christie was seated next to Haley but was not asked about the issue.
But as Christie travels to campaign for fellow Republicans as chairman of the Republican Governors Association, questions continue to pop up.
If he were to run for president, Christie "would face some challenges among the more conservative circles of our party . . . concerned about issues like Common Core and judicial activism," Bill Gustoff, a member of the Iowa Republican Party's state central committee, said this month as Christie campaigned in the state that hosts the nation's first presidential nominating contest.
"He'd have to explain his positions," Gustoff said.
Staff writer Maddie Hanna contributed to this article.