Obviously the three little words that matter most in a marriage are "I was wrong". In that context they lead to forgiveness, sooner or later. In politics on the other hand they are the inevitable precursor to weeks of public scorn and wounding criticism, which is why politicians seldom utter them. They approach the press conference lectern intending to say them but at the last minute they can't bring themselves to do it and retreat instead into a tongue no man other than a politician ever used. They "mis-spoke". Or in the case of Obama's clarification over what he said about the Henry Gates case they "could have calibrated words differently".
This is a very subtle way of putting things, as befits a very subtle man. It suggests he should have said things in a different way while also, by employing a term often used in the world of artillery, implying that had he known the impact his words would have had, he would have pointed them at somebody else. How he must yearn for the days when Presidents weren't expected to have a quotable reaction to every small convulsion in the nation's daily life.