China
It's interesting how we can overlook this sort of thing if it means we can get cheap T-shirts and consumer electronics. The sad thing is that it's not as if people don't know about the Chinese authorities stamping on democratic movements. If they sell us cheap stuff then hey, they can have our money (even if it's for the skin of executed prisoners for injection into our lips).
What's the solution? I imagine that a total ban on imports would cripple businesses the depend on the near-slave labour available in China, so how about setting a level of duty that rises every month until China does something about its human rights abuses? I'm suggesting we enforce democracy, but we can make trade dependent on their government stopping events like the one in the linked story. If we continue to trade with them without some sort of real pressure then what sort of people does that make us?