ABC News was first to air the infamous tape of parts of Wright's sermons on March 12â€”after the Iowa caucuses, New Hampshire primary, Super Tuesday primaries and caucuses and several other key contests. By then, Barack Obama had a strong hold on the nomination. Once the tape aired, Obama's poll numbers dropped and he struggled the rest of the primary season, barely limping home the nominee.
Had the Clinton team found the tape and dropped it at a strategic point during those early contests, Obama would have been toast. There's really not much question of this.
The haunting part of this from the Clinton perspective is that the sermon tapes were available online and at Wright's church. A basic job of negative research would have found them.
An ABC News review of dozens of Rev. Wright's sermons, offered for sale by the church, found repeated denunciations of the U.S. based on what he described as his reading of the Gospels and the treatment of black Americans.
In the negative research business, this is malpractice. The Obama campaign also screwed up by not finding the tape in advance and removing it from the church and internet.
This was the unpublicized turning point of the campaign.