The mayors of New York and Chicago are exasperated about the crisis of illegal immigrants flooding into their cities. Millions have crossed our southern border, and in the last 18 months some 100,000 have pushed into New York City. Another 30,000 illegal immigrants have flooded into Chicago. Now both mayors have asked for billions of dollars in federal aid to provide screening, housing, and health care. But this problem exists in the first place because the federal government failed to do its job and keep our border secure. Border security affects all of us, and our largest cities are left with a political and humanitarian crisis—which is becoming the most important domestic issue of our day.