Write a paper about how Jose the illegal keeps legal immigrant Quon from ever coming to America. How Quon, who lives in poverty, saves and works for years to legally apply to immigrate, and then waits, and waits, while Jose runs over the border. Ask if it is fair or just if someone can break the law and be rewarded (and defended) while law abiders wait and wait. That way, you ask a multicultural vs multicultural question.
For bonus points, actually interview legal immigrants who had to pay and wait and wait to come here.
ETA: This one probably requires you to research the quota system and the INS methods for determining/recommending immigration numbers, so if you don't want to do that research or don't understand basic statistical modeling, don't bother with this subject.