It's an argument with a legal basis in the Constitution. No, I didn't brief it here. As much as I enjoy Sherdog, that's too much energy for a forum post. If you want to see the argument fleshed out, just read the moving papers in the AL case I linked.
That's completely wrong. In fact, that's among the first illusions shattered by a law school education. Of course the Court is guided by policy implications, because the Court is aware that
every decision they make reflects policy priorities. Where do you think "qualified immunity" came from? Where do you think "reasonable expectation of privacy" came from? Why do you think "due process" encompasses pretty much everything under the sun? The academic debate between legal formalism and legal realism has been settled for a long time.
Like you said, "there isn't anywhere in the Constitution that limits the Census to ciitizens [sic] or to voters." Some have argued, as you do, that this places upon the government an affirmative obligation to count all "persons" in the census, regardless of legal status. Other people, like myself, point out that the Constitution was written for "
We the People of the United States," and that counting illegal aliens gives them representation that was intended for "the People of the United States."
If this case goes before the Court, the Court must make a decision. They will be making policy either way, and there will be "practical" implications. If they decide "persons" includes illegal aliens, they will be effectively enfranchising aliens at the expense of citizens. If they decide "persons" does not include illegal aliens, it will increase the political representation of citizens at the expense of illegal aliens.
What do you think Madison would say if you asked him about apportioning seats to 20+ million illegal aliens? Because in
Federalist No. 54, he was talking about slaves (specifically, to justify the 3/5 compromise). You have a pretty expansive view of Madison's reasoning.
And more to the point, using your reasoning, is there any person on Earth (other than a non-taxed "Indian") who wouldn't qualify to be counted in the census? It seems like the only qualification would be mere presence in the USA or its territories. Do you not see how that goes against common sense?