You can lose your green card status. It's not guarantee that you'll always be allowed to stay here. If you're involved in particular in criminal activity, you can find yourself in immigration court. The other thing that sometimes slithers up on people is kind of an involuntary manner that they lose their green card. That is they're out of the country too long and the government can consider that person to have abandoned their green card. Essentially, the government says, "you said you were going to be here and enjoy the benefits and we gave it to you, but now you're spending too much time out of this country. We're going to determine that you've lost your green card based on your time out of the country." you need to be very careful. It's always good to make sure you're working with an attorney to make sure you don't lose that valuable card.