In America only about 50% of us can be bothered to vote in a Presidential election, far less in congressional and local elections. So out of the people who do vote most are ideologues with a strong affiliation to a particular party. They usually cancel each other out. 20% D, 20% R. That effectively puts control of our Democracy into the hands of less than 10% of the population with some variation to be factored in for voter turnout. At the risk of generalizing these people often make their choices based on fear and ignorance. Some small subset of these people are true independents making informed choices but most are just jumping to whatever party is offering the easy answers and a good talking points.