A recent Tennessean article by Phil Valentine addresses the controversy:
There's a move to keep illegal immigrants from participating in the census. I know, most of you didn't even know they were allowed to participate, but currently there's no law prohibiting an illegal immigrants [sic] from filling out a census form and sending it in.
Mr. Valentine outlines some of the important issues at stake. Some people for instance, charge that not allowing illegal immigrants to participate is racist. Valentine contends that allowing them to participate warps our political process because census data is used to apportion congressional districts and illegals are not citizens.
When the U.S. Constitution was written, major slave-holding states insisted that slaves be included in district apportionment though they weren't citizens, while states with fewer or no slaves objected, leading eventually to the "3/5s" compromise, counting each slave as 3/5s of a person for the purposes of congressional apportionment.
Should states with more illegal immigrants have more of a voice in Congress? Would the effect be liberalization of immigration law, or interestingly- stricter immigration laws?
Another question is simply how much data we want to have. Should the U.S. deliberately try to collect less demographic data on people who are living here just because they are not citizens? Wouldn't we want to have as much information as possible to understand as accurately as possible, the demographic makeup of our country?