The terms communism and socialism are sometimes used interchangeably. This is mostly appropriate, as they are similar systems. Socialism is considered an economic system, while communism can be considered both an economic and political system. The problem with this is that socialists have to use the political system in order to enforce their desired economic system.
Both communism and socialism are systems where the state owns the means of production. The advocates of these systems will say that the public or working class would own the means of production, but this ultimately means that the state owns and controls the means of production.
Some will say that property ownership can still be allowed in a socialist system, but then this would negate the system of being fully socialist. It would be a mixed economy. Many people who call themselves socialists really are not full-blown socialists when it comes down to it. They just want more government control than what currently exists. If they believed in full-blown socialism, then they wouldn’t be able to own the clothes on their back or have any money.
Regardless of how you define the terms, communism is an extreme form of socialism. Communism happens when socialism is brought to its logical conclusion. If socialism isn’t fully followed, then elements of the market economy have to be let in.
This is why it is virtually inevitable that all true communist regimes resort to massive violence. It is no coincidence that the most brutal tyrants in history existed in communist systems. You can certainly have brutal tyrants existing in a system that is not communist, but they are less likely to get away with mass murder of their own people.
Stalin, Hitler, and Mao were some of the most brutal dictators of the 20th century, and really in history. Hitler was considered a national socialist, and Stalin and Mao were considered communist. While Germany was never completely socialist, it certainly headed in that direction under Hitler. In China and the Soviet Union, these were about as communist as you can get. But even here, they weren’t ever 100% communist. There were always elements of the underground economy. There had to be, or else nearly everyone would have starved to death.
Even if you had a populace that was completely cooperative, it would still be impossible to have a fully communist system without violence. As Ludwig von Mises pointed out nearly 100 years ago, socialism cannot work because there is no rational price system to allocate scarce resources. You will end up in extreme poverty.
Of course, any country with a substantial population will never be fully cooperative. There may be a good portion of the population that implicitly consents to the state, but you will always have people who don’t go along. You will especially have people who don’t go along when they are starving with little to lose. Even some of the most obedient citizens will rebel if they are desperate enough.
But even if every citizen were obedient, then they would either die of mass starvation, or else the state would have to let some market elements breathe within the system.
The state rests on violence. That is the definition of government in today’s world. A government is defined as the only entity with a legal monopoly over the use of violence within certain boundaries (unless the government shares that monopoly with another government).
Socialism and communism take this use of violence to an extreme. If the state owns and controls everything, then the people under that state have no say. If they rebel in any way, they risk having violence used against them.
You may hear some people advocate democratic socialism, but this is essentially an impossibility when dealing with any substantial population. If the state owns the means of production, then the people can’t really have a voice. And what happens if the people vote in favor of freer markets?
You may hear reference to democratic socialism in places such as Norway or Sweden, but these aren’t socialist countries. They are welfare states to a certain degree, but they are nothing close to actual socialism. They have a system of English common law where property rights are upheld to a great degree, or at least up to the point that the welfare state allows.
In a system of full-blown socialism or communism, there has to be violence in order to maintain the system to any degree. If violence is not employed, then it will no longer be a fully socialist/ communist system. If voluntary exchanges are allowed, this entails some form of private ownership. The communist regime can either choose to use the firing squad, or it can choose to allow market elements to leak in. There really is no third way.
The closest thing to a communist regime today is North Korea. But even there, there is some semblance of property rights and limited trade. After that, there are varying degrees of socialism and free markets. Every country has a mixed economy, but some are more socialist than others.
The reason that communism and socialism have directly led to the deaths of hundreds of millions of people in history is not a result of the systems being implemented the “wrong way”, as the socialists today would say (if they even admit to the mass murder). These systems worked exactly as they were supposed to work. In order to maintain a system of socialism and communism, you have to resort to massive violence.