Anyone who has ever had a political science class knows that the United States not a Democracy, but really a Republic. In a true Democracy when a law is proposed everyone in the country would vote on it, instead of representatives.
I think that, as technology progresses, the ability to have a true Democracy could be possible. You could log in daily to “My Democracy” and view proposed bills/laws and then vote on them from the comfort of your home. Would everyone participate? No, but if only a few thousand from around the country participated it would have to be more representative than the current system.
We’d still have a leader and a judicial branch, but the legisliative branch would be the entire US public. It would be interesting, to say the least. For now, I’d take the ability to simply vote on federal laws directly (which many states do in the form of “propositions”).