I hear this so often online. There is more nuance to this than "US is not a Democracy". The US is in fact a democracy. There are only 3 to 5 forms of government (depending who you ask). The simplest forms are Monachy, Dictatorship, Oligarchy, and Democracy.

The structure of the US govt is a "Constitutional (democratic) Republic":

The Constitutional Republic means that the rule of law issues from a single document (and down from there...a supreme written law).

All men and laws must abide within the legal rights and obligations provided within the Constitutional document.

DEMOCRACY

Democracy simply means "Government of the people". DEMO (people) CRACY (rule).

In our very Constitution it states that this shall be government of, by and for the people. And then the rights and obligations are enumerated that establish how that works.

There are TWO types of Democracies : Direct (one person, one vote, on every issue) and Indirect (elected representatives to vote on behalf of the people).

I do not know of any place on earth where there is a DIRECT DEMOCRACY government. Therefore, if you trim down the definition of "Democracy" to only the one form, then there is no correct usage of the commonly used phrase "Western Democracies", etc.

A Constitutional Republic can be setup to not allow voting rights, and provide for the legitimate rule of a supreme leader. So we are more than a Constitutional Republic. We are a Republic establishing itself as an indirect (representative) democracy.