The concept of Socialism is a pretty good idea. It believes that there should be a safety net to support the needy.
No problem there. Anybody with a Judaeo-Christian or Buddhist based code of morality is more or less behind the ideas of simple charity and 'do unto others' bit that underpins social fairness.
(Theoretically Animism can also approach this concept, but like most other 'tribal' religions - from Marxist to Muslim to Labour to Greenie - the specificity of the 'them versus us component' makes this a bit problematical in application... And please note that there are many supposed Jews or Christians who have fallen into the trap of tribalism, and many Muslims or Marxists who honestly believe they can avoid tribalism without abandoning the tenets of their religion... None of them seem to have a clue about what their professed beliefs actually require of them.)
But I digress.
Socialism as an ideal of providing a safety net and an opportunity is a wonderful thing, and I, and many others, would fight to maintain that safety net.
Socialism as a political movement pursuing 'equality' however, is one of the great evils of human invention.
Humans cannot be made equal, no matter how ruthlessly this is attempted. Humans can be given equality of opportunity, but thy cannot be 'made' to be equal. (The best image of this recently was in the Joss Whedonfilm 'Firefly' where the government wants to create 'a world without sin',and where they will keep idealistically trying to make people 'better', no matter how appalling the results of their experiments.)
People who profess to be socialists in the last century include Adolf Hitler, Joseph Stalin, Mao Tse Tung, and just about every nasty dictatorship currently operating in Africa or South America. (Some of the nasty dictatorships in the Middle East and Africa and Asia - from Iran to Somalia to South Korea - are blatant religious dictatorships... but again with a tribal perspective, not any Judaeo-Christian concepts.)
Now, obviously, the answer there is that just because people say they are socialists, does not mean they really are. Politicians lying about their real motives to fool the gullible is about as traditional as it gets.
But there are many politicians who say they are socialist who really mean it. Unfortunately their definition of socialism is so distorted, that I find them far more dangerous the obvious liars.
Socialism as proposed by most of the political parties with the word 'socialist' in their title usually just means dictatorship under a cloak of respectability that they hope the ignorant peasants and stupid media will fall for. Anything called a ‘Soviet Socialist Republic’ or just a ‘Socialist Republic’ will inevitably fit this box… eventually.
There is an excellent and amusing section in one of Robert Heinlein's worse books – Time Enough for Love – that defines politicians.
Heinlein says there are basically two types of politicians, Business, and Conviction. Business politicians rely on keeping their word, as their only saleable asset. They live or die politically by delivering or not delivering.
Conviction politicians by contrast, 'believe' in a 'cause'. They believe so passionately, that they can be easily convinced to change their promises by any new 'idea' or 'evidence' that comes along (at least if it fits their prejudices). The truly dangerous thing about such people is not that they reverse themselves 3 times before breakfast, but that each time they convince themselves (or at least can pretend to), that they are doing it for the 'good' of the people and cause they 'believe' in.
As a result they are more than willing to look their constituents (who are not necessarily the voters) in the eye, and claim their reversals were a genuine attempt to reach the goal that everyone is striving for... for the greater good of course.
The simple fact is that ‘business’ and ‘conviction’ politicians usually cannot understand each other's rationales or motives, as they are almost completely incomprehensible to them. Instead they both tend to assume that anyone with the opposite perspective is either mad, or just completely dishonest and working for completely different motives than their stated ones.
(Unfortunately, people being people, they will be right in enough cases to allow them the luxury of painting everyone they do not understand with the same broad stroke of tar. This sort of lazy self righteousness is what forms the basis of 'them and us' thinking, and is the bane of all political compromise through human history.)
It would be nice to think that willingness to change a viewpoint is part of education or just growing up. The amusing aphorism "If you're not a socialist at 20 you don't have a heart, if you're still a socialist at 40 you don't have a brain", would be less scary if it actually reflected a consistent pattern... but it doesn't.
The vast majority of humanity takes the childhood illusion they grew up with as unreflected gospel for their entire life, and is appalled that anyone could dare to disagree. (I use the word 'gospel' here with malice aforethought. The unreflecting religious being almost as dangerous as the unreflecting atheist in taking the most simplistic and childish understanding of their preferred viewpoint and trying to bludgeon everyone else with it. Religious wars are bad enough, the ‘crusades’ by Fascists and Marxists in the last century have added new meaning to repression and genocide.)
Reflection from adult understanding (particularly after the brain reaches the age of considering consequences at about 24 or 25... not at the extreme of idealistic illusion at University age of about 18 to 21) is absolutely vital to making a childhood preference into a reasoned position. Pity so few people take the time to do it...
One of the dangers of our democratic political system is that we let people start playing 'seriously' with politics at exactly the worst age. Political parties collecting university students is like shooting fish in a barrel, but the modern practice of recruiting them to the party structure in a straight line – student politician, political staffer, party professional, safe seat – (with no real life experience to intervene), means that many modern politicians do not get the mental space to reflect on what they think they believe in until several years in office trying and failing to deliver their childish ideal finally convinces them that they were either very wrong, or at least very naive.
Unfortunately this can then have it's own problems. You sometimes get the overly simplistic from both sides responding to the discovery of the unreality of what they were attempting by veering widely (and almost equally unreflectingly) to the opposite perspective... Such people often adopt equally (or even more scarily) unrealistic simplifications of a world view. (In Australia the most famously pathetic example is the ex-Liberal Prime Minister Malcolm Fraser, but 'reborn' ex socialists or communists are often even more worrying in their fanaticism!)
Or, perhaps worse, they simply decide that they will keep mouthing the words they don't believe in any more, in a ruthless attempt to get power... Not that they really want to achieve anything particular any more... just get power.
So how to choose the lesser of two evils?
1. Given a choice of politicians who 'believe' unreflectingly in childish idealism, always go for the conservative, not the radical. It will slow progress to a pathetic crawl, but there will be a lot less bloodshed. (Shedding blood is necessary sometimes, but conservative reasons like 'defence of traditional liberties' – aka English or American Revolutions – is always better than blood shed to 'save the world and remake it in perfection' aka French or Communist revolutions, or almost any religious war...)
2. Given the choice of politicians who genuinely believe, after genuine adult reflection, they are working for the common good, again you should always go for the business one not the conviction one... you may not like the result, but it will at least it may resemble what they were originally talking about.
3. Give the choice between politicians who only pretend to believe in what they are promoting, go for the business politician anyway. They may only be in it to line their pockets and enjoy the fruits of power, but, because they live or die by keeping heir word, they will only stay in it by making the trains run on time. Corrupt but competent is always going to do less damage to the society than well meaning but incompetent.
A 'true believer' is always going to throw public money at anything that sounds good anyway, and is always surprised the result is often the opposite of what was intended. (Education 'improvements' that lead to mass illiteracy; workplace 'improvements' that lead to mass unemployment'; health 'improvements' that lead to failing hospitals; etc.) But a cynic pretending to be a true believer stays in power despite incompetence by throwing money at things they know won't work just to claim they are doing something. (And to buy voted of course... but they all do that...)
4. But given the choice between two socialists: one of whom says they accept the world is imperfect, but believe in the justice of a safety net; and one of whom really truly believes that equality in all things is both desirable and achievable... go for the sane one. The raving lunatic can only finish one of two ways. Disillusioned and corrupt, or so convinced in their cause that they eventually have to make themselves all powerful to make it happen because they can find no other way. (Stalin and HItler are great example of the first, and Cromwell and Mao are fun examples of the second. And note, I have chosen supposedly ‘right’ and supposedly ‘left’ versions in both samples to make the appropriate mockery of ‘right’ versus ‘left’.)
It is probable that through history the majority of so called Socialists who have achieved and grimly maintained power until their society collapses under the dead weight of extreme socialism (as Churchill said, 'the problem is they eventually run out of other people's money') have been the first... just corrupt shadows of their original so called beliefs. This would include almost any socialist government elected over too long periods in Southern and Eastern Europe (and Ireland, which counts as 'southern') or in Central or South America. They just slowly drag their countries down to a level of poverty and violence that it was their stated intention to replace with their idealised utopia. (Prime examples of mouthing without meaning would include Stalin, the Castro's, Chavez, and the current dynasty in North Korea.)
The real problem though, is the ones who continue to believe in their dream, and are willing to do whatever it takes, including seizing all power for themselves, to see it happen. Cromwell, Robespierre, Lenin, Mao, Pol Pot, Idi Amin, Mugabe, and Adolf Hitler are all 'conviction' socialists (almost all of them with some sort of claim to be elected leaders of republican forms of government) who took their societies to the extremes they felt were necessary to achieve the purity they genuinely believed in...
Historically, socialism for the goal of a safety net will inevitably reduce the overall living standards, education, employment, and opportunities, of a society... but not necessarily destroy it completely. (Or at least not yet, in the cases of places like Scandinavia which are back-pedalling fast on the excesses that reduced the PIIGS –Portugal, Italy, Ireland, Greece and Spain - to basket cases with up to 50% youth unemployment). It can even be argued that some of this equalisation might be a good thing, but the long term reduction of living standards over the admittedly less pleasant chaos of more free flowing capitalism is the inevitable price.
But historically Socialism for the goal of a fantasy ideal of universal equality and wealth will lead to the nastiest and most bloody dictatorships in human history. (On a scale that would make even a tribal barbarian lunatic like Genghis Khan green with envy.)
If you love the idea of 'safety net socialism', as I do, and are willing to accept a limited diminution in overall living standards to achieve it: be very, very afraid of the 'ideal' of 'perfect Socialism'. The more people unreflectingly pursue an impossible dream, the less chance the reflecting have of achieving some sort of reality.