Try this in Google. Same three words, just reverse the order. "Bush mocks Kerry". "Kerry mocks Bush".
The first one returns 145 news articles on Google news and 7,110 web pages on regular Google. "Kerry mocks Bush"? One news article and 254 web pages.
Bush's campaign, by the most conservative calculation, is 27 times more likely to mock his opponent than is Kerry. Google news reflects more recent data than Google main and therefore implies that Bush is heaping on the mockery at an increasing pace--145 to 1.
The general tone is more revealing than the specific issues. Kerry's campaign uses criticism and comparison and sometimes resorts to mockery. For Bush mockery is the main, and sometimes the only tactic.
This is the behavior of an angry, petulant schoolyard bully. Like the bully, he wants something he does not deserve and is using words as weapons rather than to convey meaning.
This behavior plays well with angry white men of a certain age. It is less endearing to mothers who almost inevitably will have seen some other kid do it to their child.