There's also the tenth amendment if you need more evidence that the constitution grants power to the people.

The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.

The constitution is immediately established a document of the people in the first three words.

And again democracy from ancient Greek demos meaning people and kratos meaning power is literally translated to power of the people.

Nowhere does the ancient Greek meaning require direct voting, simply power. The people controlling who is in charge gives all the power to the people. In the US that's voting citizens