I agree with your reading of it but would suggest it need only be a noncontradictory and nonpretextual reason; e.g., "I have determined that a citizenship question is in the country's best interest."
<> Non-citizens Have Large Impact On Congressional Apportionment <>
Immigration has a significant effect on the distribution of seats in the U.S. House of Representatives for three reasons.
First, seats are apportioned based on each state’s total population relative to the rest of the country, including illegal aliens and other non-citizens.
Second, congress has chosen to allow in a large number of legal immigrants and to tolerate wide spread illegal immigration. After the 2000 Census, the average congressional district had roughly 650,000 people. Thus, the more than 18 million non-citizens in the 2000 Census were equal to nearly 29 congressional seats.
The third reason is that non-citizens are not evenly distributed throughout the country. In 2000, half of all non-citizens lived in just three states and almost 70 percent live in just six states. States with a large non-citizen population will gain at the expense of states comprised mostly of citizens.