Mitt Romney’s presidential campaign has responded to the increased focus on Jon Huntsman’s service as Ambassador to China by parroting an attack line from conservative blogger Erick Erickson.

After Huntsman criticized Romney this weekend for engaging in divisive politics by attacking Huntsman’s service in the Obama Administration, Romney responded by dispatching a high profile surrogate to attack Huntsman’s loyalty to the President.

“I tell you, I wonder about Jon Huntsman’s integrity,” New Jersey Governor Chris Christie said at a Monday morning rally. “What was he doing in China preparing to run for president? Because this doesn’t happen overnight.”

If this line of attack seems familiar, it’s because conservative RedState blogger Erick Erickson began using it way back in May:

The reason I will never, ever support Jon Huntman is simple: While serving as the United States Ambassador to China, our greatest strategic adversary, Jon Huntsman began plotting to run against the President of the United States. This calls into question his loyalty not just to the President of the United States, but also his loyalty to his country over his own naked ambition.

Although Erickson has since joined the Huntsman chapter of the “anyone but Mitt” society, he clearly tapped into a channel of conservative mistrust of Huntsman which Romney is now trying to revive.