I don't think we are obligated to do anything. I don't even necessarily support all of the illegals getting citizenship. It is a very sensitive issue with a lot to consider, and like I said in my earlier post, I recognize the threat they pose to the right wing. I actually like your common market idea. I just don't like it when illegals are blamed for things that are not their fault, like the lack of jobs in this country. I also don't believe that if given citizenship all of the illegals would become a bunch of welfare leeching Democrats.
It's a problem because we have suddenly become a country in which citizenship confers financial benefits. It was not originally intended to be this way. Originally, the intent of the constitution of the USA was to confer rights upon people and to ensure those rights were enforced. It was not to provide a livelihood to people in exchange for their voting for a particular political party.
The whole purpose of immigration laws is to protect socialism. As Milton Friedman said, a socialist nation with open borders will collapse upon itself. That's why I believe open borders ultimately protect us from socialism.
There does not seem to be room for an open borders person in the current debate, however. One side wants to give away the farm and the other side wants to take away an inalienable human freedom (property rights, ie my labor is my property) from people.