Where can I read up on this? A friend of mine (legal resident) was questioned at a port of entry and the officers were "considering whether to admit him in or not", as he said. He's of Pakistani descent, and he always gets harassed coming into the US. Now that I read a similar story here, I would like to know if it's really up to the passport control officers whether to admit legal residents or not. If this is left to their discretion, there is no difference between a tourist visa and permanent residency.
Don't be facetious. A tourist visa has an expiration date within days or a few months at most and does not permit you to work or study in the United States. A green card has no expiration date and lets you do almost anything in the United States that a citizen can do. Being a permanent resident also gives you a chance to become a citizen within a few years, whereas you can't have any intention to remain in the USA if you want a tourist visa.
It is true that immigration has almost as much discretion with permanent residents as tourists,but that doesn't make the two statuses the same.
I'm sorry for your friend, but screening is not harassment and if he was merely questioned and admitted your friend has no grounds for complaint. There are legitimate, sensible, and easily understandable reasons to screen Pakistanis more thoroughly than Swedes, for instances. Your friend can apply for citizenship in a few years and then he will have the right to be treated the same as other Americans.