How come things only look up after a Democrat becomes president.?

Although I support the Democratic party, it's not the Republican party's fault that these things happened. We were kind of forced to go to war no matter who was President--we had a tip that Osama bin Laden was producing weapons of mass destruction, and we kind of don't want to get blown up. However, now that bin Laden is out of the way, things might look up. But you still can't blame America's current economy drop on the Republicans, and much less George Bush.