The Constitution states, "The House of Representatives shall be composed of Members chosen every second Year by the People of the several States...". Contrast this with the original constitutional language for the other house of Congress, "The Senate of the United States shall be composed of two Senators from each State, chosen by the Legislature thereof for six Years..." The phrase "chosen by the Legislature" was changed to "elected by the people" by the 17th Amendment, but not until 1912. In other words, from the beginning the House of Representatives was intended to be exactly what its name suggests -representative of the people.
Textbook models suggest how members of the House of Representatives may fulfill their constitutional duty to "represent" - the delegate model, the trustee model, the oversight model, and the service model. A weakness of these models is that they ignore the pervasive influence of interest groups, partisanship, and political money on the behavior of congressional reps. To what extent do these factors interfere with effective representation?