To some conservatives it is "explosive" unseen footage that shows Barack Obama playing the race card, the perfect retaliation to the devastating Mitt Romney 47% video.

But within minutes of the five-year-old video of Obama being released by the Daily Caller website on Tuesday night, the "exclusive" began to unwind amid criticism that much of it had been reported at the time and the content was anything but explosive.

The 40-minute video – released in a carefully choreographed operation between Daily Caller editor-in-chief Tucker Carlson, Fox News host Sean Hannity and Drudge Report founder Matt Drudge – was shot in Virginia in June 2007 as Obama was campaigning for the Democratic presidential nomination.

It covered a speech to a mainly black audience in which he accused the federal government of failing to provide sufficient monetary help for the victims in New Orleans of Hurricane Katrina, contrasting this with the assistance given to New York after 9/11.

He suggested that this may have been because the federal government did not care as much as the victims of Hurricane Katrina, who were mainly black.

"What's happening down in New Orleans? Where's your dollar? ... Tells me that somehow the people down in New Orleans they don't care about as much.

Obama is also seen as praising his pastor in Chicago, the Reverend Jeremiah Wright, whom he was to disown the following year. "My pastor, the guy who puts up with me, counsels me, listens to my wife complain about me. He's a friend and a great leader. Not just in Chicago, but all across the country," he said.

In the speech, Obama also questioned the wisdom of spending money on roads in the suburbs when what was needed were jobs in the inner cities.

The Daily Caller published the full video on its website on Tuesday night. In what it described as an exclusive, it said: "A barely-recognisable Obama lavishes praise on Rev. Wright ... says feds 'don't care' about black New Orleans ... claims gov't spends too much on suburbs, not 'our neighbourhoods'.

On his Fox News show, Hannity described it as "a glimpse into the real mind of Barack Obama. It is pretty explosive stuff". He claimed the mainstream media were guilty of hiding the speech.

Carlson, appearing on the show with him, claimed Obama had put on a fake accent to appeal to a black audience.

But the video is unlikely to have much impact on the presidential race, unlike the secret video obtained by Mother Jones of Romney's "47%" remarks that went viral and have done serious damage to his campaign.

Reporters, including Carlson, covered the speech at the time, as did Fox and the other television networks. Carlson insisted on Tuesday that journalists only reported on a copy given to them by the Obama campaign at the time and did not see his unscripted remarks.

On his show, Hannity contrasted Obama's praise for Wright in 2007 with his condemnation of Wright in March the following year, implying hypocrisy. But Obama only disowned Wright after video footage was shown of a fiery rant by the pastor denouncing America and said at the time he did so with a heavy heart, acknowledging how important he had been in his life.

Hannity did not have it all his own way on his show. Fox political analyst Juan Williams, who is black, accused him of playing the race card.

The Democratic national committee described the conservative attack as "lame".

The bigger question is whether the Romney campaign played any part in the release of the footage. Both campaigns can be guilty of dirty tricks operations, passing on material to sympathetic journalists. But Romney officials denied all knowledge and distanced itself from the video, portraying it as thin.

The test will come in the presidential debate on Wednesday night and whether Romney ignores it or uses it as a tit-for-tat with Obama when he raises the 47% video.