(promoted from comments)
Leaving aside the fact that historically probably 90% of all our ancestors were illegal immigrants (even my ancestors who came over on the Mayflower were violating the King's charter, which allowed them to settle only in Virginia), here's why Conservatives should LOVE illegal immigrants.
They're the embodiments of entrepreneurial capitalism, family values, respect for authority, fiscal responsibility, and devotion to the military. Details on the flip.
(1) Social Darwinism / entrepreneurial free enterprise at its best. These folks have showed initiative, cunning, and ingenuity in getting into the country in the first place, figuring out how to get around the rules and regulations concerning their livelihood, and carving out a niche for themselves. Unlike their lazy and dumb counterparts who stayed at home. Why, it's the enterpreneurial spirit, in retail. They're the cream of the crop of their native lands, and we only want the best in the U S of A.
(2) Family Values. By far the vast majority of illegal immigrants come to this country to care for their families, and virtually all of them come from deeply conservative religious traditions.
(3) Fearful respect for authority. While most of us live our lives with the delusion of having rights and liberties which are inalienable, illegal immigrants know that if they're caught spitting on the sidewalk they may be deported. This creates an incredibly law-abiding populace. My Aunt in San Diego calls the right-hand lane of the I-5, where traffic crawls along at a lawful 55 at all times, the "illegales lane" because nobody wants to get caught in a routine traffic stop and find themselves heading back to Sonora.
(4) Cost-free support of massive federal spending. Contrary to popular belief, illegal immigrants don't drain social resources such as welfare and public assistance programs. With fake documents to get jobs, most illegals end up contributing payroll taxes, and some income taxes, for which they will never collect retirement or other benefits. (This is not a joke, just yesterday they readjusted the timeline for Social Security Trust Fund solvency based on calculating the contributions of immigrants who will never cash out benefits.) Given our deficits, it would be far more fiscally responsible to invite even more illegales in.
(5) Support for our armed forces. The fastest-growing demographic enlisting in our armed forces are non-citizens. If we're going to have enough cannon fodder for further foreign adventures without a liberty-depriving draft, what better way than to continue to rely on the patriotism and love of country of foreign-born illegal immigrants who have come for the opportunity and stayed for the adventure of a lifetime.
Tell me, where else are you going to find conservative values in such density except among the illegal immigrant population?