Would a neutral United States prevent the Second World War?

Would the Second World War still happen if the United States had remained neutral in the First World War?

Probably yes; the key difference would be a harsher, less moderated post-war order and the likely absence of the Washington Naval Treaty.

The post-war diplomatic settlement matters more than the simple fact of American participation. Without the United States at the peace table, there may be no Washington Naval Treaty and less moderating pressure on Versailles. The United States would also emerge with less influence and a weaker reputation for confronting major powers.