Ms Tree said:
So how do you ban Muslims?
Exactly. That section was used by Presidents to restrict or temporarily stop immigration from certain countries during times of war, or when Carter used it to make all Iranians validate visas during the hostage crisis.
Banning based on religion does not meet the legal test. If a president used that to ban certain people carrying certain passports, it would be upheld. To my knowledge, no passport from any country identifies ones religion.
That is also only federal code, states cannot ban immigration. The supremacy clause would stop them from doing that. Just look at what happened in Texas to see that proven.
This guy has written a pretty good piece on this and put in the correct context:
http://www.powerlineblog.com/archives/2015/12/as-usual-trump-and-his-critics-are-both-over-the-top.php
"Whether it is a good idea to suspend immigration from predominantly Islamic countries is debatable on the merits. But this alternative is plainly legal, is entirely workable, requires no inquiry into any individuals religious beliefs (except to the extent that refugees cases are considered), and could be implemented tomorrow if President Obama signed the necessary proclamation.
If hysteria on both sides subsides, this approach could lead to a healthy discussion of several immigration issues. Such a discussion could start with the question, why do we need immigrants from, for example, Pakistan? Why are we better off with them than without them? What are the costs and benefits? How well have such immigrants assimilated in the recent past? How is such immigration affecting American workers?
Sadly, the immigration debate these days is dominated by voices on both sides that are hyperbolic, bordering on the hysterical."