Comment by DeusExMachina

Basing layoff decisions on citizenship is likely illegal, and that's why no company does that. It does not mean, however, that they can't do it by proxy. If you lay off people above a certain salary and justify it as cost cutting, yoiu are likely targeting mostly nationals. The few H1B caught in the net are just collateral damage. Then, you can hire imported workers that are willing to work for far less just to have a chance to come to America.