Slavery and human trafficking
A U.S. Government report published in 2003 states that between 800 000 and 900 000 people worldwide are trafficked across borders each year, against their will. This does not even include those trafficked internally.
This not just a moral issue (although it most definitely is that); it is affront to that core concept of freedom that we hold dear. It is not just rhetoric; freedom is a true luxury in many parts of the world.