ST. PAUL — An independent ad featuring a fellow prisoner of war questioning John McCain’s ability to be president is a “nightmare” for Barack Obama, former Pennsylvania Sen. Rick Santorum (R) said Wednesday.

In the ad, Philip Butler says he would not like to see McCain in the White House because of the POW experience and the Arizona senator’s temperament.

“I think I can say with authority that the prisoner-of-war experience is not a good prerequisite for president of the United States,” Butler says in the ad, which was produced by Brave New PAC, a political action committee associated with the liberal film company Brave New Films.

Brave New Films has no affiliation with the Democratic presidential candidate or his campaign. Neither presidential campaign responded to requests for comments.

Santorum, who was among the leading social conservatives when he served in the Senate, called the ad “disrespectful.”

“I think it is scandalous and disrespectful to a man who has obviously sacrificed greatly for his country,” he said, adding that it is Sen. Obama’s (Ill.) “nightmare that some crazy group suggests that because someone served his country and sacrificed for his country, that he is not capable to lead.”

Santorum suggested the ad is “so outrageous that Barack Obama should be pleading for these people to take it off the air.”

The ad buy is reminiscent of the 2004 election, when a group of soldiers, who had served with then-Democratic nominee John Kerry in Vietnam, appeared in ads slamming the Massachusetts senator. Kerry’s slow response to the attacks is widely seen as one of the reasons he lost the race. Butler was an outspoken supporter of the Democrat in 2004.

However, Butler told The Hill that he believes the circumstances are different.

“The Swift Boaters tried to demean John Kerry’s service,” Butler stated. “You don’t hear me doing this to John McCain. I’m not talking about his service, I’m talking about the man.”

He stressed that he holds “no grudge” against the Arizona senator.

“I like John,” Butler said, adding that he has “great respect” for him.

Leighton Woodhouse, a spokesman for Brave New Films, said the 30-second ad will air on CNN, MSNBC and ESPN from Thursday through the weekend.

Obama and his Democratic surrogates have repeatedly raised questions about McCain’s temperament, but they have praised his war record.

Butler said he supports the Democrat but has not been in touch with the campaign. He added that he would not agree to have the ad pulled even if the Obama campaign asked Brave New Films to do so.