The median voter

From, a project of Institute for Humane Studies:

Why Do Politicians All Sound the Same?

Could you tell the difference between Barack Obama and Mitt Romney during the last election debates? To many people, they sounded more or less the same. If you’re wondering why this was the case, it’s not because they agree. During elections, political party platforms move to the middle, to attract what is called the “median voter”, essentially, the Independents and the voters closest to the middle. A Democrat expects to get votes from the most extreme Democrats, and a Republican expects to get votes from the most extreme Republicans. In a two-party system, there usually isn’t another viable option to vote for.