I don't understand why anyone would want to continue to return to an idea that has repeatedly failed and done so with gusto.
Doesn't socialism's track record speak for itself, in its enormous capacity to lead to widespread poverty and human rights abuses?
And don't point to Scandinavia because those are only socialist countries to people who don't really know what socialism is.
No, Scandinavia's socialism is exactly what democratic socialism is. Communism is likely what you're thinking of and all of us know the distinctions. I'm going to spend a moment to drop a few names just because the tropes about socialism are tired and mostly a result of the 50 years of brainwashing most people received as a result of the Cold War.
Eduard Bernstein
Karl Kautsky
Vladimir Lenin
Rosa Luxemburg
Leon Trotsky
In the early part of the 1900s, the socialists of the world were organized in what was called the 2nd international. There had been a first international, which Marx and Engels were a part of, but the 2nd international was what succeeded it, and all the figures above were part of it.
Eduard Bernstein was friendly with Marx before his death and knew Engels pretty well. He had risen in prominence in the international but became known as the father of what was often derisively called "revisionism." He critiqued Marx's works fairly exhaustively, including his reliance on Hegel's dialectics, his understanding of some aspects of economics, and his view of history as deterministically predictive. He thought revolution was overrated and that instead the transitions to socialism would be a long and gradual process through democratic processes. He also believed capitalism had its uses and that unions were the mechanism to bring about worker ownership of the means of production rather than total state centralized control.
After he published his works, he was attacked by everyone else on the list above. Luxemburg basically called him a sellout. Lenin called him a traitor. Even Kautsky, a moderate, thought Bernstein was completely out to lunch and an embarrassment.
But many others in the International did not feel this way. The German and British socialists in particular were intrigued by a socialism based on possibility rather than radical disjuncture. Bernstein went on to campaign in Germany as part of what then became known as the Democratic Socialist Party (SPD), but Bismarck, in his authoritarian crackdown, expelled all socialists from government. Bernstein fled to England for awhile but returned around the turn of the century, where he and other SPD members were elected to the Reichstag.
Unfortunately the Second International fell apart shortly thereafter just as Bernstein's influence was growing. World War I had come and most socialists who were in elected offices voted to extend their countries war credits as paranoia was rampant over who might attack first. Revisionist Bernstein and centrist Kautsky were among these who chose country over ideology, at least at first. This incensed people like Lenin, Luxemburg and Trotsky who considered it a betrayal and denounced their comrades as disloyal to the principles of revolution. The second international dissolved at the outbreak of war and Bernstein immediately reversed his position, strenuously opposing the war and the breakdown of diplomacy. It was too late.
Shortly thereafter, Lenin and Trotsky were victorious in Russia following the fall of the Tsar. By virtue of having finally "won" an entire nation, their brand of communism became ascendant and the revisionists were a lot less sexy. Revolutionary Marxism suddenly seemed not only possible, but probable. Leadership of the reconstituted International devolved to the Russians.
Following the war, as Germany struggled to rebuild, Bernstein and Kautsky united to form an independent social democratic party. Lenin and Trotsky's pogroms and alienation of the trade unions disenchanted some among the party who refocused their own efforts on party building along revisionist lines in their respective nations. In the US, the revisionist social democratic movement would take hold among people like John Dewey, who inspired much of the modern public education system and had analogues in the ideologies of the likes of Eugene V. Debs.
In the US, many socialists gradually crept rightward and supported Leninism or became Trotskyites following Trotsky's expulsion by Stalin from the party. Following WW2 the revisionist ideals would grow to be dominant among socialists in Europe (including the Scandinavian countries, England, and France, all of whose reform movements focused on building electoral blocs and gradual improvements to society informed by Marx's critique of capital, but not devoted to revolution and certainly at arms length from Stalinism. Meanwhile Leninist movements sprouted up in places like Cuba and China, where Mao Tse Tung would invent his own brand of communism.
By the 1970s, there were a number of factions among socialists and the group calling itself the Socialist party USA, whose platform included total opposition to the Soviet communist ideology and, in simple terms, much of what Bernstein had recommended decades prior, eventually transformed into the Democratic Socialists of America, or DSA. This is the group to which Alexandria Ocasio Cortez belongs, as do people like Cornel West, author Barbara Erenreich and actor Danny Glover. Bernie Sanders ideology is also generally aligned, though is more in the mold of FDR's New Deal Democratic platform than DSA proper.
I write all this so I never have to write it again on this forum. Hopefully this post can be a guide on the factionalism that's really always been inherent in socialism, among which, this is only a small part as there have been hundreds of factions and interpretations both before and after Marx. Just as there is a tea party, an alt right, libertarians, neocons, the Koch apparatus, evangelicals, Burkean conservatives etc in the conservative movement, socialism has had a varied and complicated history. People who lump it all in as one are mostly operating under the brainwashing of the Cold War or similarly reductive ahistorical arguments.
A great book on the history of the ideology is
Main Currents of Marxism, The Founders, The Golden Age, The Breakdown by Lescek Kolakowski. Kolakowski was a Polish communist who became disenchanted with the party and eventually left in disgust, which makes his account one of the most interesting because it's from the inside out. There are plenty of other great histories, but Kolakowski's is widely considered the most comprehensive and one of the most well researched.
Even now there is widespread debate among socialists about both Ocasio Cortez and Bernie. Many feel, for example, that Bernie's endorsing anti-choice candidates is antithetical to socialist praxis. Others feel Ocasio Cortez's whole campaign shouldn't be supported because the focus should be on building an independent socialist party, not reformism within the corporatist Democratic party. Still others have come out en masse to deride Cynthia Nixon, who recently declared herself a socialist in what many people see as sheer opportunism to take advantage of youthful enthusiasm for socialism in New York and as a way to position herself against the notably centrist Andrew Cuomo in the gubernatorial primary.
This factionalism is what makes the process democratic, after all, and is distinct from "dictatorships of the proletariat" and central committees, as in Leninism. When I say I'm a socialist, this is what I mean. I support the messy process of democracy to bring about collective ownership of enterprise by workers, a robust commitment of the state to social welfare and public works, and individual rights to freedom and opportunity. The devil, as always, is in the details, but that's to be decided democratically and will only happen when people want it enough.