The political needs and wants of citizens vary on a very broad spectrum based on their differing locations.  What is good for those in New York City is not necessarily the same for those in say Sioux Falls, SD - heck, the politics in Lake Pleasant, NY vastly differ from those in Brooklyn, NY.  Different locations of a state can have completely distinctive interests from one another.  So, when it comes to national politics, you have to take into account these diverse demographics because policies will often be viewed differently.