John Sununu, the former governor of New Hampshire and top surrogate for Mitt Romney, has stoked controversy several times this election cycle. (Andrew Innerarity/Reuters)

When John H. Sununu suggested Thursday night that former secretary of State Colin Powell endorsed President Obama because both are African American, it was not the first time the former governor of New Hampshire and top surrogate for Mitt Romney had stoked controversy this election cycle.

“Frankly, when you take a look at Colin Powell, you have to wonder whether that’s an endorsement based on issues or whether he’s got a slightly different reason for preferring President Obama,” Sununu said in an interview on CNN. When pressed on what those reasons might be, he replied, “Well, I think when you have somebody of your own race that you’re proud of being president of the United States, I applaud Colin for standing with him.”

Powell, a former chairman of the Joint Chiefs who served as George W. Bush’s chief diplomat, endorsed Obama earlier Thursday. He also endorsed the Democrat in 2008.

Sununu quickly backed off his remark, saying in a follow-up statement after the interview that Powell is a friend and, “I respect the endorsement decision he made, and I do not doubt that it was based on anything but his support of the President’s policies. [CNN’s] Piers Morgan’s question was whether Colin Powell should leave the party, and I don’t think he should.”

Sununu, who served as chief of staff to former president George H.W. Bush, has been one of Romney’s most active surrogates. He’s appeared to embrace the role of campaign attack dog, lambasting Obama at every turn, from cable news interviews to conference calls with reporters. Along the way, his brash, outspoken manner has prompted criticism from opponents.

Sununu’s remarks have ranged from implying that Obama is un-American to calling the president “lazy” for his lackluster performance at his first debate against Romney.

“I wish this president would learn how to be an American,” Sununu said of Obama during a July conference call in which he took the president to task for his handling of the economy. The remark triggered pushback from Democrats, and a walkback from Sununu himself.

Appearing on MSNBC the day after Romney’s first debate with Obama, Sununu said of the president: “He didn’t want to prepare for this debate. He’s lazy and disengaged.”

MSNBC’s Andrea Mitchell, who conducted the interview, gave Sununu an opportunity to clarify whether he was indeed calling the president lazy. Sununu replied, in no uncertain terms, that he was.

In a Friday interview with Philadelphia radio host Michael Smerconish, Obama brushed aside Sununu’s initial assessment of Powell’s endorsement.

“I don’t think that there are many people in America who would question General Powell’s credibility, his patriotism, his willingness to tell it straight,” the president told Smerconish. “So any suggestion that General Powell would make such a profound statement in such an important election based on anything other than what he thought would be best for America doesn’t make much sense.”

In a Friday interview with CNN, Newark Mayor Cory Booker (D), a prominent Obama surrogate, said Sununu’s statement about Powell was insensitive.

“Whatever he meant or not, it was a statement that is unfortunate and just reflects a lack of understanding and sensitivity,” said Booker, who is African American.

Romney spokeswoman Amanda Henneberg said Sununu’s comment Thursday night “did not reflect the views of the campaign, and he was right to clarify it.”

Rachel Weiner and Aaron Blake contributed to this report.