Well, I don't think it's ever worked, but then again I don't think it's ever failed either. The only time it was on the cards, between 1917-23, so many communists were murdered that the revolution failed.
By my reckoning, what was set up in Russia wasn't communism, because communism is the establishment of a worldwide, classless, communal society without money, and that's not what happened.
So it has to be worldwide, thereby abolishing all countries, and it has to abolish money and profit (commodity production in fact), exchange and incidently a 'working class'. All will have to be done away with.
It will also do away with 'government' - the 'government of people will be replaced by the administration of things'. I don't see a problem with instability though. It's capitalism that's unstable, as current events show. Oh, and I think, given that capitalist society is collapsing around our ears, that this is very current...
"Well it's Forty-one Thousand Nine Hundred Sixty-nine OK -
Gotta war across the Milky Way - "
Iggius Popiscus and the Stoogii, "41,969"