Ilan Pappé writes:
The one-state solution has a troubled history. It began as a soft Zionist concept of Jewish settlers, some of whom were leading intellectuals in their community, who wished to reconcile colonialism and humanism. They were looking for a way that would not require the settlers either to return to their homelands or to give up the idea of a new Jewish life in the “redeemed” ancient homeland. They were also moved by more practical considerations, such as the relatively small number of Jewish settlers within a solid Palestinian majority. They offered binationalism within one modern state. They found some Palestinian partners when the settlers arrived in the 1920s but were soon manipulated by the Zionist leadership to serve that movement’s strategy and then disappeared into the margins of history.
In the 1930s, notable members among them, such as Yehuda Magnes, were appointed as emissaries by the Zionist leadership for talks with the Arab Higher Committee. Magnes and his colleagues genuinely believed, then and in retrospect, that they served as harbingers of peace, but in fact they were sent to gauge the impulses and aspirations on the other side, so as to defeat it in due course. They existed in one form or another until the end of the Mandate. Their only potential ally, the Palestine Communist Party, for a while endorsed their idea of binationalism, but in the crucial final years of the Mandate, adopted the principle of partition as the only solution (admittedly due to orders from Moscow rather than out of a natural growth of its ideology). So by 1947, there was no significant support for the idea on either the Zionist or Palestinian side. Moreover, it seems that there was no genuine desire locally or regionally to look for a local solution and it was left to the international community to propose one.
The appearance in 1947 of the one-state solution as an international option is a chapter of history very few know about or bother to revisit. It is worth remembering that at one given point during the discussions and deliberations of UNSCOP (the United Nations Special Committee on Palestine, February to November 1947), those members of the UN who were not under the influence of either the United States or the USSR—and they were not many—regarded the idea of one state in Palestine as the best solution for the conflict. They defined it as a democratic unitary state, where citizenship would be equal and not determined on the basis of ethnicity or nationality. The indigenous population was defined as those who were in Palestine at that time, nearly two million people who were mostly Palestinians. When their idea was put in a minority report of UNSCOP (the majority report was the basis for the famous [or infamous] Resolution 181 of November 29, 1947), half of the then members of the UN General Assembly supported it, before succumbing to pressure by the superpowers to vote in favor of the partition resolution. It is not surprising in hindsight that people around the world, who did not feel, like the Western powers did, that the creation of a Jewish state at the expense of the Palestinians was the best compensation for the horrors of the Holocaust, would support the unitary state. After all the Jewish community in Palestine was made of newcomers and settlers, and were only one-third of the overall population. But common decency and sense were not allowed to play a role where Palestine was concerned.