Worry more about the border patrol and policies. For example, are you aware that when the border patrol "catches" an illegal immigrant, the immigrant is processed using whatever ID the immigrant wants to provide and a court date is set 30 days in the future. The immigrant is released IN THE US and gives a "gentlemen's agreement" to show up in court. Of course no immigrant ever does. There are large communities of illegal immigrants working in the US and not paying taxes. If "terrorism" was a real problem, then the US would have caved in destructively by a civil war by now. The bigger problem is the loss of manufacturing jobs and the wasting of billions of dollars on "terrorism" and "drug abuse". Don't give the US government any more excuses to waste money. Get rid of lawyers and ACLU reps that prevent any type of effective policy from being used.
a lot of the stuff that you said is not accurate. first of there are immigrants that do pay taxes, but by being immigrants they do not get any refunds, and are in a way paying to get deported. and if they pay taxes they might get deported, just think about it, it is illegal for them to work, so if they declare that they work they are, if a certain law passes, commiting a felony, it may not be a good idea to pay taxes if you are going to be charged with a felony for doing so. Rememmber they are human being they have to work, and its not like they are getting a high pay, they are getting a lower pay, they are in many cases being cheated out of their money because technically they are not supposed to work so its easier for an employer to steal money or not pay them because there is nothing that the immigrant can do. and if they do get paid, its not as much as you may be thinking. In many cases the jobs that they work for are generally jobs that would not be taken by a US citizen because of safety and low paying issues.
Take this into consideration, if we outlaw immigration all of a sudden the chances for a terrorist to hide are very high, since there are allready 11 million undocumented immigrants (estimated), it means that the terrorist can hide in a group of 11 million people, but if we make immigration legal, it means that there would be no reason for someone not to be able to identify themselves, it destroys the illigal immigration business, and it makes it easier to protect against terrorism since we would be able to know who is in this country and who is not. There we have taken care of two major problems by allowing something. But then that would mean that immigrants do not have to be afraid of paying their taxes, or of getting deported for doing, well anything for that matter, since if they are arrested for any reason, even if not their fault, they may be deported. The cost of deporting immigrants is estimated at $41 billion "The study estimates that it would cost about $28 billion per year to apprehend illegal immigrants, $6 billion a year to detain them, $500 million for extra beds, $4 billion to secure borders, $2 million to legally process them and $1.6 billion to bus or fly them home." according to the washington post
http://www.washingtonpost.com/wp-dyn/content/article/2005/07/25/AR2005072501605.htmlThe reason that we have immigration is because immigration is illegal, it makes a business that is, though illegal, highly profitable, which means that immigrants can get in easily, and that illegal documentation becomes a profitable business for any one with the knowledge of how to do it.