I guess it depends on what you mean by "works".
Obviously there are some big, powerful countries that operate under Communism. They appear to be functioning, even though they obviously have problems. But then there are some democratic countries that appear to have problems too.
If you mean, is Communism in practice congruent with its stated ideals? Probably not. But then again, the functioning of any country is probably far from ideal.
In conclusion, I'm not a communist, so please don't blackball me.