Liberals had the election "in the bag" in 2000 & 2004, and still lost. What is so different now?

The media keeps claiming the election is over before it starts, and every time, the results prove differently. Why is 2008 so different? Obamunists claim the election has been over for a while, but they did that with Gore & Kerry, and lost both times. Why would anyone in their right mind think that the media will succeed this time in controlling the vote?