Is it true that Obama defeated Bush and not Mc Cain?

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Is it true that Obama did not defeat Mc Cain, but Obama defeated Bush instead? Bush is a republican who supports Mc Cain's candidacy. But people all over the world are suspecting that Americans chose a democrat (Obama) over a republican (Mc Cain) because they are traumatized from being faced of the crisis that Bush (a republican) has made them experience. Is it rightful for Americans to throw away Mc Cain and his potentials just because he is also a republican? What can u say about this?