President Obama made a number of gaffes (e.g., not knowing the difference between the summer and winter olympics; and not knowing where major U.S. ports are) in his Leno appearance. Had they been made by a Republican president (remember how George W. Bush's gaffes were played up by the press?) you can bet the Associated Press would have headlined them rather than making up an explanation and inserting it as part of the original quotation.
Then there is the Associated Press bias:
.@ap Hm. You jump all over a Sarah Palin gaffe http://t.co/IYmvDedcvx ...but cover up Obama's. http://t.co/6YoMJnKv8m
— Michelle Malkin (@michellemalkin) August 7, 2013