Because the census (since at least 1980) has not distinguished citizens and permanent, legal residents from individuals here illegally, the basis for apportionment of House seats has been skewed. According to the Census Bureau’s latest American Community Survey data (2007), states with a significant net gain in population by inclusion of noncitizens include Arizona, California, Florida, Illinois, Nevada, New Jersey, New York and Texas. (There are tiny net gains for Hawaii and Massachusetts.)

This makes a real difference. Here’s why:

According to the latest American Community Survey, California has 5,622,422 noncitizens in its population of 36,264,467. Based on our round-number projection of a decade-end population in that state of 37,000,000 (including 5,750,000 noncitizens), California would have 57 members in the newly reapportioned U.S. House of Representatives.

However, with noncitizens not included for purposes of reapportionment, California would have 48 House seats (based on an estimated 308 million total population in 2010 with 283 million citizens, or 650,000 citizens per House seat). Using a similar projection, Texas would have 38 House members with noncitizens included. With only citizens counted, it would be entitled to 34 members.