The controversy: Whether or not the US Census should include questions relating to a respondent's citizenship status.
My answer in the column was correct as far as it went: The purpose of the census is to count noses, period, end of story. Any other demands for information exceed the census's constitutional mandate.
But there's another good argument that a "citizenship question" specifically has zilch to do with that mandate. Let's look at the text from Article I, Section 2:
Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers, which shall be determined by adding to the whole Number of free Persons, including those bound to Service for a Term of Years, and excluding Indians not taxed, three fifths of all other Persons.
The "three fifths of all other persons" referred to slaves, of course, and that became irrelevant with the 13th Amendment.
But what's the relevance of "Indians not taxed?"
Simple: A popular sentiment leading up to the American Revolution was "no taxation without representation."
This text, by codifying the reverse of that -- no representation without taxation -- affirms the original. Indians living within the claimed jurisdiction of the US who were not taxed were not to be counted in the census ... and everyone who paid taxes was to be counted in the census.
Non-citizens might not be able to participate in choosing their (supposed) representation (by voting), but they still got that (supposed) representation by being counted in the census such that their numbers were reflected in the apportionment of US Representatives. And, as the now vestigial text on slave counting indicates, they got full representation.
QED, there's no constitutional reason for the census to ask a citizenship question, because a non-citizen counts exactly as much toward congressional apportionment as a citizen does.
The usual disclaimer: Yes, I am still an anarchist and want to see the system described above smashed to bits and salt sown in the earth where it once stood. I'm setting aside questions like whether or not the state should be allowed to exist, whether or not the constitutional system constitutes anything like legitimate "representation," etc., above for the purpose of considering the question on that system's own terms.