Article I, Section 2 of the constitution requires the government to conduct a decennial census, and empowers congress to make such law as it may direct to imple

Article I, Section 2 of the constitution requires the government to conduct a decennial census, and empowers congress to make such law as it may direct to implement it. One could easily see a national identity system to be justified as part of the census. I'm sure there are other articles that could also be used to justify one. The reluctance around a national identifier and system is purely policy, not lack of constitutional authority.