"Democratic Republic"

What do all these countries have in common?

• Republic of Cuba
• People's Republic of China
• Democratic Republic of the Congo
• Democratic People's Republic of Korea (North Korea)

Give up? They are all countries which are known for oppression, violence, and/or war, and they all have names talking about how democratic and republican they are. I guess if you don't have a democratic country, you can try to convince people that you do by saying that you do.

It's more likely that whoever named these places wanted them to be democratic and republican, but the system broke down, or, in some cases, never really got off the ground. Why is it so hard to put together a good democracy?