How come every election its the most importan election for the party who is not in power?

For each party every presidential election is critical because it has significant impact on the next presidential race. It means the opposition party will be setting policy for the next four years, and the possibility of the incumbent party stealing voters from the other parties based. Or losing voters in the case of George W. Bush who turned out to be one of the best things to ever happen to the Democratic party - particularly Barack Obama. Had Gore won in 2000 and spent 2 terms in office the country surely would have never been ready for a Black President so soon, which is sad because a leader shouldn't be judged on the color of their skin. Infact 12 years of Democratic rule would have almost certainly have put a Republican President in office in 2004 and by 2008 because of the shift in demographics Hilary Clinton would mostly certainly have been the President of the United States right now. Obama's chances of becoming POTUS would have been faint to nonexistent. One can say that the stars must've been aligned in Obama's favor from birth .

However I will say that for both Parties this is the most important election since either parties conception. For the Republicans it means losing an entire generation of voters again because of the shift in demographics in the country and the shift in opinions of American values. The father the country moves right or left the harder for the other party to win support for their ideas. If the Democrats lose it could have a significant impact of the course of the nation for the next 10-20 years, by the appointment of two conservative judges who will tip the law of the land in weigh of the Republicans Party. Unless something as tragic as 9/11 happens again Americans are going to continue to want to move forward on social issues and break free traditional inhibitions. In the end both sides are afraid to compromise too much

They want to fire up their supporters to donate $ and vote. Making the election seems like a desperate battle suits their needs.