As conservative opposition to the national K-12 education standards known as Common Core continues to grow, a leading figure in the Republican Party is lending his voice in support of the system.

Former Arkansas Gov. Mike Huckabee, who ran for his party’s presidential nomination in 2008, penned a letter Tuesday to lawmakers in Oklahoma, urging them to stick by the standards even as Michigan, Indiana and other states have backed away from them.

“It’s disturbing to me there have been criticisms of these standards directed by other conservatives,” he said. “I’ve heard the argument these standards ‘threaten local control’ of what’s being taught in Oklahoma classrooms. Speaking from one conservative to another, let me assure you this simply is not true … They’re not something to be afraid of; indeed they are something to embrace.”

His letter came on the same day that the Michigan state senate passed a budget blocking all funding for Common Core. That measure now heads to the desk of Republican Gov. Rick Snyder, who like Mr. Huckabee, is a strong supporter of the standards.

Indiana already has paused implementation of the system, becoming the first state in the nation to do so.

Leaders in other states, such as North Carolina, have indicated they may follow suit.

North Carolina Lt. Gov. Dan Forest — who also holds a spot on the state’s Board of Education — said his state ought to take a step back and re-evaluate Common Core.

“Perhaps a fresh set of eyes will give us reason to pause, and make sure out state looks before we leap into the Common Core,” he said, according to the Charlotte Observer.

The standards have come under increasing fire from conservatives who see them as a de facto federal takeover of education. While the Obama administration didn’t have a hand in writing Common Core, it has pushed states to adopt the standards by tying its ” Race to the Top’ grant money and other perks to their implementation.

Common Core doesn’t establish a national curriculum but instead lays out specific facts and concepts students are expected to master at the end of each grade level, with the ultimate goal of increasing college and career readiness among American young people.

The standards were written through a joint effort of the National Governors Association and the Council of Chief State School Officers. Many governors from both sides of the aisle, including Mr. Huckabee, Mr. Snyder and former Florida Gov. Jeb Bush, continue to be among their most fervent supporters.