The progressive left has always been based on a coalition of the oppressed or marginalized; in the West, this is now taken to include the poor, women, racial minorities, and sometimes gays and lesbians. But the actual constituents of the coalition evidently change over time, as after all, originally the coalition only included the working poor and, specifically to the US, racial minorities. More importantly, the groups that are considered working poor or oppressed racial minorities change over time. A good case study for this is the experience of Jews, who the left considered a racial minority on a par with black Americans throughout the West until about the 1960s. Although at least in the US Jews still tend left, the association between them and movement progressivism is weaker for reasons that are indicative of how the left operates as a whole.
The reflexive reason is that Israeli actions became increasingly consistent with right-wing politics. In 1967, Israel turned from a perpetually threatened country to a country so strong that it could destroy its neighbors’ air forces while their planes were still on the ground. Later it also became an explicitly occupying force that funded settlements in the West Bank and the Gaza Strip, which from a left-wing perspective changed Zionism from an anti-colonialist or anti-racist ideology to an imperialist one. That is certainly the underlying concern of modern left-wing opposition to Israel.
But in fact, something else had to be at stake. When two countries billed as post- or anti-colonialist fight, the left tends to blame historical imperialism. When the Second Congo War tore Congo-Kinshasa apart, the left-wing response was not to blame the Rwandan Tutsis, who invaded the Congo and plundered its natural resources, or the Hutus, who were responsible to the greatest atrocities. Rather, it was to blame Western colonialism for Africa’s problems and to cast the war as a scramble for resources demanded by the capitalist system. Although it was possible to narrate the Arab-Israeli conflict from a pro-Israel, anti-colonialist view, emphasizing Britain’s divide and rule tactics, the left chose not to. Such a narrative would later become impossible to make because of the settlements and the brutality of the occupation, but the Western left broke with Jewish groups in the 1960s and early 1970s, before the first settlements were built.
Therefore, a better explanation for the expulsion of Jewish groups from the coalition of the oppressed has to lie in domestic trends in the United States, which held a plurality of the world’s Jews. The most obvious explanation given that constraint—namely, that discrimination against Jews abated after World War Two to the point that in the US Jews were more like Italians and Poles and less like blacks and Hispanics—is helpful, but it still seems like only part of the reason.
A different part likely comes, ultimately, from different experiences with oppression. In the last six or seven hundred years, anti-Semitism has taken predominantly legal and cultural forms, reinforced by the occasional pogrom. Earlier than that it had an economic dimension—Jews were forbidden to own land—but once Europe recovered from the Dark Ages, the professions that Jews dominated, such as banking, turned them into a prosperous minority. This trend has existed since then almost continuously, with a brief break among Jewish immigrants to the United States around the turn of the 19th century. But even then, many of the poverty-based experiences that shaped black civil rights activism just didn’t exist among Jews.
Equipped with an intellectual culture closer in its emphasis on book learning to this of China than to this of the West and a skin color that made it possible for Jews to pass as gentiles in certain cases, Jews came to dominate such skilled professions as the law, medicine, and the academia. Discrimination against Jews was therefore more about explicit restrictions than about the economic impoverishment that typified anti-black racism. For example, in the 1920s Harvard moved from a purely meritocratic admission system to its current system in order to reduce the percentage of Jewish students from 25 to 15; at the time, Jews consisted of 2% of the American population. In contrast, only recently have blacks stopped to be underrepresented in American universities in general, to say nothing of elite universities.
As such, Jewish civil rights activism was predominantly legal, consisting of fights against discriminatory laws. Since most Jews at the time also came from a socialist or sometimes liberal political tradition, they naturally lent their groups—the ACLU and the Anti-Defamation League—to supporting similar equal rights struggles, primarily those of black people but sometimes also those of labor. As long as that was how left-wing activism worked, the ACLU and the ADL were natural allies of the black civil rights movement. More importantly, once black civil rights activism changed its focus to economic issues, the natural link was severed.
Although in the 1920s and 30s there was a strong socialist element to Jewish thought, by the 1950s and 60s it was replaced with straight liberalism. The most committed socialists were Zionist enough to immigrate to Israel and merge into city or kibbutz life. Anti-communist witchhunts exercised pressure to repudiate socialism. Several decades of life in the United States exercised pressure to adopt one of the two acceptable ideologies in the country, liberalism and conservatism, abetted by the fact that upward mobility plunged most Jews into the middle class. Those trends most visibly affected the ACLU, separating it from the unions.
And perhaps most importantly, after the early 60s, the most pressing legal battles were no longer racial. There was a growing realization in parts of the left, especially but not only the liberal ones, that there were marginalized groups not defined by class or race. Second wave feminism drained many Jewish liberals away from racial civil rights struggles; while within anti-racist activist groups Jews could define themselves as another racial minority, once Jewish liberals diverted their energies to other civil rights struggles the blacks who dominated the civil rights movement could now define Jews as whites. The animosity between feminists and anti-racists over who was more oppressed and therefore had a greater priority certainly didn’t help.
Those blacks were certainly within reason. Jews could change their names and pass for white gentiles while blacks and the new minority in search of civil rights, Hispanics, couldn’t. The Holocaust made racism generally unfashionable, but especially affected anti-Semitism. Especially after Martin Luther King’s assassination, the black civil rights movement had shifted its focus to poverty-related issues, while the ACLU’s civil liberties battles were increasingly class-neutral. Lacking any domestic discrimination to focus on, Jews who wanted to focus on specifically Jewish issues gravitated to support for Israel, which would’ve separated them from the mainstream American left, whose only involvement in foreign policy was anti-war activism, even if it hadn’t entailed support for Republican hawks.
Thence by 1970s the relationship between Jews and blacks had strained to the point that the American left stopped considering Zionism an ally. American Jews have still leaned left since then, but Zionism, which historically was a left-wing movement, was tagged as right-wing.
It’s important to note that it was only after domestic trends within the United States had separated Jews from the anti-racist left that the left started to view Zionism as right-wing. The Six-Day War could provide a suitable pretext for viewing Israel as an oppressor state rather than as an oppressed state, but the right-wing characteristics of Zionism, namely a singular emphasis on military service and discrimination against Arabs, date back to Israel’s independence. Today’s anti-Israeli leftists even trace right-wing Zionism further back than that—for example, Noam Chomsky blames Zionists for the initial friction between Jews and Arabs in the 1920s—but those interpretations only arose after the fact. As long as Zionism was considered left-wing, the left would forgive its transgressions just like it did those of other socialist or post-colonial states.
The significance of this to the left in general is that the answer to the perennial question of which groups are considered oppressed and therefore get the associated fringe benefits is determined by many things that have little to do with oppression. A group that is no longer oppressed may still receive these benefits if politically it’s still aligned with other left-wing movements; conversely, a group that is still oppressed but fails to side politically with the mainstream left, or a group that is oppressed but cannot convince anyone that it is, will be perceived as not deserving any special recognition.