Is it constitutional to ask all immigrants to carry proof of legal standing at all times?

In the USA, it's the job of the Supreme Court to answer questions of constitutionality.

To my knowledge, none of the Justices of the S.C. is a regular contributor to , so you'd need to bring your case through the normal channels.

If it were I writing the opinion on that question, I could write a simple, direct answer of probably less than 10 pages, that would boil down to "No. You've got to be kidding."

For one thing, how would you know that somebody walking down the street is an immigrant, unless they were also required to tattoo "FURRINER" on their forehead ?

I don't know if they were the most recent example, but certainly the most notorious example of an evil regime that required certain portions of the population to carry "papers" and provide them on demand was Hitler's reich of the 1930s and 40s.

china unilaterally claims the entire south china sea as sovereign territory, then builds artificial islands to bolster its claim. it suddenly activates an air defense identification zone over the east china sea, and threatens to down any aircraft that does not report its position. it builds roads into indian territory, then redraws the maps to show that it is actually chinese territory. the people's republic under president xi jinping is quickly becoming the bully of asia.

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.