In contrast to a capitalist system, socialist regimes invariably transform into authoritarian or totalitarian political regimes; regardless of whether they reached power through popular vote or revolution.
That revolution often ends up in non-democratic regimes is an historical fact that can be explained by the revolutionaries desire to cling to power, regardless of whether they are pro or anti-socialists and anti-democracy.
What needs explaining is why socialists who were voted into power and promised to respect democracy also turned into non-democratic regimes. We can find two different routes.
First, when socialism evolves into communism. Then, it necessarily abandons its pro-democracy ideals because communism was based on the concept of a class (proletariat) dictatorship later renamed popular democracy.
Whether socialism will inevitably degenerate into communism was already debated in the XIX century. For instance, in Bastiat’s Law (1850), the author claimed that “men will resort to plunder whenever plunder is easier than work… As soon as the plundered classes gain political power, they establish a system of reprisals against other classes. They do not abolish legal plunder”.
Indeed, one hundred years later, a similar pessimism about human nature was the basis for Schumpeter’s (1942) prediction that capitalism would degenerate into a form of corporatism to be replaced by socialism.
Fortunately, history has shown that socialism does not always evolves into national socialism or communism and sometimes reverses into social-democracy, which accepts both capitalism and democracy. However, as the Scandinavian experience shows, this reversion has to be substantial otherwise the regime will not survive.
There is another possibility for socialism to survive temporarily within a democracy by exploring what we may call Latin-American populism.
The most emblematic example is found in Venezuela, a country with the oldest bipartisan democracy in the region. Former President Hugo Chavez was elected with the support of a largely impoverished population which was “bribed” to re-elect him through state sponsored social programs paid by the middle classes and the un-economic exploitation of the rich natural resources of the country for the benefit of a small group of trusted cronies.
However, this model of socialism is inevitably doomed for two main reasons: 1) the economic inefficiency of the system is so high that even the dilapidation of natural resources is not to enough to hide a generalized economic decline, and 2) the demands of its supporters on the welfare state rises with any new benefit so that public finances soon collapse.
These two factors are abundantly seen in Venezuela, where the socialist rulers, faced with growing opposition, have introduced all sorts of paranoiac prohibitions and persecutions in order to hang on to power, including the prohibition of travelling abroad for media directors and the detention of the opposition leader.
In conclusion, socialism will inevitably send democracy to a kind of limbo, from which it is only possible to exit by reversing its path towards social-democracy or by evolving towards state capitalism or communism and dictatorship.