"I will not be attending this year’s convention, nor any Republican convention in the future," Huntsman told the Salt Lake Tribune on Friday. “Until the party focuses on a bigger, bolder, more confident future for the United States — a future based on problem solving, inclusiveness and a willingness to address the trust deficit, which is every bit as corrosive as our fiscal and economic deficits."

Huntsman, who served as ambassador to China under President Obama, ran as a centrist in the Republican primaries, but he was one of the few candidates never to surge in the polls as an alternative Mitt Romney, as primary voters were skeptical of his commitment to conservative principles.

"I encourage a return to the party we have been in the past," Huntsman continued. “From Lincoln right on through to Reagan, that was always willing to put our country before politics."

It’s the former Utah governor’s latest dig against his party. Earlier this month, Huntsman joined the liberal-leaning research and policy group The Brookings Institution as a distinguished fellow.

Huntsman has endorsed Romney.