What do modern day democracies have in common with Athens today and why does representative democracy work better for the United States?

Democratic techniques in the modern world have embodied the ideology of democracy, but the overall structure has been diluted over time. "The dominant ideologies in modern capitalist states have tended to dilute the democratic idea, to dissolve it altogether into the concept of liberalism, to offer liberalism not as a complement to, but as a substitute for, democracy as popular power"