No. To do would be to imply that it regretted the action. This would be very politically unpopular amongst WWII veterans, their children, and many others. A solid majority (some 60%) of Americans today think Hiroshima and Nagasaki were justified — a rare point of agreement on a polarizing political topic. (Only 22% were opposed to it; the rest were undecided.)

The official US position has been, since August 1945, that Hiroshima and Nagasaki were unfortunate but necessary because of the behavior of the Empire of Japan and because the alternatives were worse. People have debated that ever since, but I would not expect any US President to express otherwise until well after the last WWII veteran has died, if not the last child of a WWII veteran. Support for the bombing varied greatly by age demographic currently; only 50% of people under the age of 50 supported it when this poll was done in 2009, whereas 75% of those over 50 supported it.

And follow up question: How has the reception of the bombing from the perspective of Japanese been / changed over the past 70 years?