Answer:
A Direct Democracy allows for the people to vote on government issues as opposed to the less direct system where we elect representatives to do the legislating and law making for us in a representative democracy.
Explanation:
If the US were a Direct Democracy, you would essentially be cutting out the checks and balances of the legislative branch. The judicial branch and executive branch may have control still but in this instance, I believe that the people would replace the legislative branch having a direct vote and say in every issue that arises at the national level.
A Representative Democracy/Constitutional Republic like we have in the US allows for the people to vote representatives based on ethics, beliefs, or even simply political party affiliation for offices like senators and presidents.
These elected officials then carry out governing us- the population- by acting within the laws of the land which are already established and legislate to introduce new laws, bills, and ammendments to the constitution as the need arises.