I don't know if companies are allowed to let immigration affect their firing decisions. But, in terms of how other human beings are treated, there is a differe

I don't know if companies are allowed to let immigration affect their firing decisions. But, in terms of how other human beings are treated, there is a difference for the holder of a temporary visa... If an H-1B visa holder is laid off or quits, the visa immediately expires. That leaves two main options: almost immediately find another job (at a company willing to spring for a new visa, no less), or leave the United States within a very short period of time. And when the economy is bad, good luck with that first "option"; the replacement job has to be visa-class, it can't just be flipping hamburgers. A temporary visa doesn't last long (1-3 years), but it's a rotten status to be in if there's a layoff. Imagine: you're living somewhere new, you've made friends, you have possessions, and suddenly in addition to having been fired your life is turned upside down; and if you don't sort it out quickly you'll be given a plane ticket and told never to return. So while companies probably aren't allowed to consider any of this when choosing who to fire, I wish they would.