Imagine that the US Supreme Court didn't decide (5-4) that 'money is speech' in Citizens United so that corporations and PACs and Unions can spend unlimited and uncontrolled amounts of money.

Just like gay marriage, five Supreme Court Justices changed the law for the entire country even though voters throughout the entire United States and in many States had voted the other way.  

Sometimes those five Justices rule the ways you like, sometimes they don't.  

Either way, those five people decide for 300 million other people.