It's actually unequally-weighted doubly indirect representation with structural incentives (but no guarantee) for the representatives actually tasked with choosing the voting representatives to both delegated that task to the citizenry and a separate set of incentives and abide by the results and a separate set of incentives (and, again, no guarantee) for the set of voting representatives to vote in accordance with the preferences expressed by the voters by whom they were elected.
And neither of those sets of incentives is, unlike the doubly-indirect structure itself, part of the federal Constitution; they are both much more recent federal statute and state law incentives.