The reason all dems protect any illegal alien is because of VOTES. This is a KNOWN fact.While i doubt a Muslim registry will occur I'm not entirely sure how the mayor of NYC has standing to challenge the federal government on it unless he is a Muslim being required to register
If this is about Muslim immigrants registering at the time of entry, I bet Trump will get it passed because his national security powers are highest at the border. If this turns into requiring current American citizens to register with the government based on religion or nation of origin, I'm guessing your movement will bump squarely into the Constitution. However, if Ginsburg and Breyer die or otherwise vacate the Supreme Court, I don't think Trump will have to worry about the Constitution.