>>12401078>marxistI don't know if there's ever really been a marxist country, communist certainly, but marx's ideas really haven't come to pass. If you just generally mean nations built on marxist thought, it mostly doesn't work because marxism is in my opinion a lot closer to philosophy than political theory, and that marx was wrong about a lot of his claims on human nature. Though I think if you want a better understanding, you should just go read marx and form your own opinions.
If you want a quick study on the rise and fall of a communist state, look at the khmer rouge. In some ways, they emphasized some of the most fundamental aspects of marxism, as a true peasant's revolution to a collective, communal society, though they were obviously also corrupted by stalinist and maoist thought. I think everyone should read at least the wikipedia page on the khmer rouge at some point anyway, and you can decide for yourself what specifically went wrong. But just in general, I think the most important issue is that marx is wrong about human nature, and communists are too extreme. Having flawed ideology is one thing, but when you refuse to adapt your systems to the realities of human nature, you're going to have a bad time.