system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does American use a Presidential system, rather than a Parliamentary one?
gpt
Because we divide our government into separate branches and use them to limit the other branches. In a parliamentary system the legislative and executive branches are fused into one, which gives it more power, and in most parliamentary systems the judicial branch is partially fused as with it as well giving it even more power. In the US they are all separate and have powers to counter the other two. 

We also prefer to have a bit more of a democratic process by voting on who we want our States to vote for as President (electoral college). In a parliamentary system you do not actually get to choose your leader at all, it is chosen by the majority party in your parliament.