In the last presidential election the polls were surprisingly accurate -- not including the massively inaccurate Election Day exit poll. In the end, Bush beat John Kerry 50.7 percent to 48.3 percent in 2004. Most of the October polls showed the candidates in a dead-heat, with Bush 1 to 3 points ahead. So either pollsters got a whole lot better starting in 2004, or Democrats stole more votes in that election than we even realized.
funny you take the one example where the polls were close and disregard the other 7 examples of when they were not