[dragonwriter]

> The house already adequately represents the people

By what standard?

> that's how it was designed.

That may have been the design goal, but it's debatable whether the original design met the goal, and key elements of the original design (the original representation ratio) were not fixed in the Constitution or preserved over time.

> Expanding the house doesn't change representation.

It changes both the equality of representation (reducing quantization artifacts) and the proximity of Representatives to the represented, both of which are key elements of representation.