Al Gore called up George W. Bush and announced he was going to concede, then called back and took his concession back. If Gore had gone ahead and conceded, would the election be over now?
No. Concession speeches are courtesies--they are not legally binding. In Florida, when an election margin is less than one-half of 1 percent, a recount is automatic. If Al Gore had conceded, the recount would still have happened. If he went on to win the recount, and Bush didn't challenge it, he would become president. But if Gore lost the recount, and didn't recant his concession, that would mean the end of his legal challenge and the end of the election.