I think it was the right move as excepting another award he had not earned would have led to a new round of ridicule. The story does not go in to detail on the 'thanks, but no thanks' letter, though it hints that it could have been a bit more tactful.
"The US President rejected the invitation from the world-leading group of scientists and instead chose to visit a south London state school.
Sources close to the state visit said members of the Royal Society were “deeply offended” by the snub and had accused Mr Obama of being obsessed with his “street cred”.
The US President was offered the chance to receive the King Charles II medal, which is awarded in “exceptional circumstances” to heads of state who have “made an outstanding contribution to furthering scientific research in their country”.
The last person to receive the medal was Angela Merkel, the German Chancellor, in 2010.
The honour was to be conferred on the US President at a dinner where he would be introduced to “some of Britain’s brightest and best young scientists” as well as some of the society’s most prestigious fellows.
But Mr Obama’s aides responded to the invitation with a “very short” note in which they said the president would rather spend time at a south London state school. "