How does the Constitution limit democracy?

The framers of the Constitution certainly placed limitations on the democratic process. While some of these limitations have been removed through the use of amendments, others remain in place to the present day.

One of the most notable, and enduring, limitations lies in the Electoral College, used to elect the president of the United States. Keep in mind, private citizens do not actually vote for candidates, they vote for electors. On a state-by-state basis, citizens elect an elector who will then cast a vote in favor a given candidate. The framers of the Constitution tended to distrust direct democracy, which they feared would devolve into mob rule.

As a second example (and one which has been changed by way of constitutional amendment), senators were originally selected by the state legislatures rather than by popular election.

As one last example, consider the entire legislative process, as well as the systems of checks and balances that it aims to maintain.