Yes. It’s a no-brainer. In fact, there is zero intelligence in not asking if a person is a citizen. Being a Citizen is NOT the same thing as being a Resident, and being a NONresident is NOT the same thing as being here illegally. It is not the same question at all as “Are you in the US legally” and cannot predict the answer to the “legally” question. No Fifth Amendment implications, no deportation threat. The idea that the question would drive illegal aliens to not be counted is bogus: the answer to the question will be the same whether you are a legal Resident Alien, legal Temporary resident, legal Student Visa holder, or an Illegal Alien. Example: I am a US citizen by birth married to a Canadian citizen who became a legal Resident Alien so that she could immigrate to the USA after we were married. My wife has never applied for US Citizenship. So if the Citizenship question shows up on the next census questionnaire in yes-or-no format, then her answer will be exactly the same as that of a person who walked in across the Arizona desert undocumented, rowed undocumented to Florida from Havana, or is a PhD candidate at MIT documented with a current Student Visa and will return to her country of origin after earning the degree. They will all answer the question honestly, “US Citizen: No”. So just ask the question, OK.