Deace, who endorsed rival Newt Gingrich before the Iowa caucuses, took offense to Romney senior adviser Eric Fehrnstrom's comments on CNN in which he decried intolerance within the party.
Grenell, a foreign policy expert who had worked as a spokesperson at the United Nations under the Bush administration, was hired by the Romney campaign last month but resigned after his appointment as a foreign policy spokesperson for Romney prompted ire from social conservatives.
"Wherever there are voices of intolerance within the party, or the Democratic Party for that matter -- it doesn't matter where it's coming from -- it's disappointing," Fehrnstrom said in an interview with CNN shortly after Grenell's resignation. "And the governor has taken the opportunity in the past to denounce those voices of intolerance."
That prompted something of an online diatribe from Deace, who tweeted at least 17 times about Fehrnstrom's comments Thursday night.
"So at the same [time] the Romney campaign is demanding loyalty pledges from its base, it calls its base `voices of intolerance,'" he wrote in one. "What Romney's spokesman did tonight was bring aid and comfort to the enemy, which is the act of a traitor," he said in another.