One item that distinguished voter perceptions of Bush 43 versus Gore was that more voters said that they'd "prefer to have a beer" with Bush. Palin fans gush that she is "just like us" in spite of her enormous wealth. Defender of geographically-challenged, inexperienced or simply incompetent candidates often insist that what makes a great leader isn't their knowledge but rather their ability to make good decisions based on information they receive from their advisors. They point to Washington, who was not known as a great thinker but had the foresight and humility to create a cabinet of advisors. They cite Lincoln, a relatively inexperienced politician who rose to the challenge. These defenders brush aside the countless examples of novices, talking-heads and puppets who left the public in much worse shape by the end of their term.
We need our leaders to be exceptional. Supporters and detractors all credited Clinton and Nixon with having exceptional intelligence and being visionaries, even if many disagreed with their vision or their less noble behaviors. Reagan was universally credited with his exceptional speaking skills.
Bush 43 was often criticized for being intellectually absent and generally completely ordinary except for the massive political and business connections he inherited from his family. Historians consider him to have been one of the worst presidents of all time though this judgment may soften over the next few decades.
Obama entered office with the same American dream myth of someone rising from nowhere that voters loved in Clinton, Reagan and Nixon. Obama has been credited by supporters and detractors for his exceptional intelligence and oratory skills though former supporters now express that he is "just another politician" who can rouse a crowd with eloquent speeches then either not follow through or, even worse, do the reverse in practice.
Over time Americans have come to expect less and less from their politicians. If you want a buddy to drink with, then go call up a friend. If you want someone to lead the world's largest economy and military then demand excellence in leadership and intelligence, not sports trivia knowledge, dart throwing skills and their eagerness to play beer pong.