Scott, does the constitution cover the rights and privelages of US citizens only or is it a constitution of the United States and everyone who happens to be here? That's the first and foremost problem I see in this whole thing. It's my belief that there are people who are covered by the constitution (ie: legal US citizens and resident aliens) and those who are not (ie everyone else). Is this a means of declaring open season to violate every person who isn't a citizen that's here, by no means, but on a very simple level they are not the same as you or I. They are not citizens or legal residents/visitors.
Once that fact is squared away, you start to look at other things. What difference does that make whether they're citizens or not? Let's just look at what the government gets out of us citizens. Taxes. A noncitizen/resident/visitor doesn't pay taxes (beyond any sales tax in the state they're located in). What do these taxes do, what do we get from the government? The government provides services for everyone, and in this case whether they're a citizen or not right now they are provided for, and that's highly unfair. Not only that, but because the smaller source of money (citizen's taxes) must cover the larger group of people. That's one of the primary drains of these people, and no ammount of cheap labor (which only helps drive down the paying wage for others) can make up for it.
And of course, don't forget that as was mentioned any illegals who do further illegal activities in this country who go before a court must find legal representation, usually provided by the government, and either housed in a corrections facility or deported (where it's very likely that they owuld just return). Who foots the bill for that? Even legal citizens who break the law pay the taxes that help fund the justice system.