Well, I don't think mexico is a bad neighbor in the sense that mexico is going to attack the u.s. like bin ladin did. However, with that being said, I think that terrorist attacks come in many forms. I don't think anyone would argue that the biggest problem of illegal aliens coming into america is from the mexican border. I think its much easier for terrorist to come by the way of mexico than by the way of canada since after sept 11, for the simple reason that the officials in mexico aren't the most honest around. This is a problem that you see in poorer countries as rule not just mexico.
I also think that their is many form of terrorist, and illegal aliens can drain the resources of a state to the point of no return! I do not blame anyone from mexico trying to come over the u.s. border in their shoes I would do the same thing. With that being said, the facts are clear that those mexican crossing the border tend not to be the most educated in their society. They tend not to contribute to the u.s. government as a whole and consume more resources than they put back. Furthermore 2nd generation don't fair as well as other 2nd generation ethnic group. HIgh drop out rate, low wages etc... This information comes from the recent LA census. Sooner or later south west states will have to look at whether they want to be like new mexico which has suffered greatly by illegal aliens in the form of sucking dry its limited resources. I'm not against letting people from mexico in the country, in fact I welcome it. I just think they have to go through the same process as any other country.
I think a big problem is that illegal aliens get the same benefit as all americans do. I for one feel that social services should be for all legal americans regardless of gender or race, not for those who are illegal.
I also blame a huge problem on both the u.s. government and the mexican government. Allowing u.s. companies to set up shop along the mexican american borders. These u.s. companies in mexico don't have to have the same environment laws that we in america do, so the rio grand that flows from mexico is now like a toxic dump. Big business big money will make governments turn a blind eye.