On the afternoon of May 14, 1948, hours before Britain’s Royal Navy flotilla would sail from Haifa harbor, marking the end of Britain’s mandatory rule over Palestine, leaders of the local Jewish community hastily assembled at the Tel Aviv Museum to hear the head of the Zionist leadership, David Ben-Gurion, declare, “The Land of Israel was the birthplace of the Jewish people. …We hereby proclaim the establishment of the Jewish State … the State of Israel.” Palestine was then in the midst of a civil war. The U.N. had decided, six months earlier, to partition the land into an Arab and a Jewish state. The Jews of Palestine accepted the plan, which gave them a majority of the land despite their making up less than a third of its inhabitants. The Arabs rejected it.

But the Jews were better organized and better armed. By May 14, they had expelled or encouraged the flight of some three hundred thousand Palestinians. The war that followed ended in 1949 with Israel expanding its boundaries to 78 percent of what had been Palestine. Within that territory, eighty percent of the Arab population had been exiled and Jews now made up a majority. To preserve it, Israel prevented the non-Jewish refugees from returning, in defiance of the U.N.’s call to allow them to come home.

Both Jewish nationalism and Palestinian nationalism came to be defined by the idea of return. Israel, which was founded on the principle that Jews had a 2,000-year-old connection to the land and a right to return to it, established unlimited immigration for any Jew in the world—regardless of national origin or links to the territory. At the same time, Israel denied return to Palestinians who had been exiled from homes they inhabited in their own lifetimes.

The return of refugees from the 1948 war became the central issue of the Israeli-Palestinian conflict. It remains a crucial sticking point today. This spring, Palestinian organizers launched the “Great March of Return,” a series of protests near the Gaza-Israel border demanding that Palestinian refugees and their descendents be allowed to return to what is now Israel.

In the aftermath of 1948, the displaced Palestinians constituted the national movement’s core constituency and main political leaders. Through armed resistance, Palestinian factions sought to liberate their homeland and obtain the return that refugees in other conflicts were routinely allowed, and that was guaranteed under international law. Israel met that resistance with violence of its own, killing thousands of refugees as they tried to sneak home under cover of darkness in the years following the war.

For eighteen years after the 1948 war, the conflict was frozen. Israel was too strong to give up territory or permit return to stateless refugees, and the Palestinians were too weak to obtain it. The great powers paid lip service to their right to return but did little to help bring it about. Then, in 1967, the paradigm changed. In the June war of that year, Israel conquered Jerusalem and the rest of the West Bank, as well as Gaza, Sinai, and the Golan Heights. Post-1967, Palestinian refugees became an addendum to the international community’s new priority, which was to achieve peace between Israel and its neighbors through the return of lands Israel took in 1967.

Over the two decades following that war, the Palestinian leadership and the Arab states moved toward a pragmatic accommodation with the reality that Israel could not be defeated. Egypt made peace with Israel in 1979. The Arab states proposed a plan for peace with Israel in 1982. In 1988, the Palestinian national movement formally relinquished the goal of liberating all of Palestine, accepting the idea of a Palestinian state alongside Israel, in just the 22 percent of the Palestinian homeland that Israel had conquered in 1967: Gaza, East Jerusalem, and the rest of the West Bank.

But it took another couple of decades and considerable bloodshed before Israel and the U.S. came around to the idea of giving Palestinians their own independent state. During the second intifada, the violent 2000-2005 uprising against Israel’s occupation, Israel, the United States, and the U.N. Security Council all formally endorsed the notion of Palestinian statehood. Then, as the intifada death toll mounted, Israel decided to withdraw its settlers and army from Gaza, maintaining control of the territory from outside, and made plans for further withdrawals in the West Bank. The Gaza retreat took place in 2005. But by then, the uprising had ended, its participants killed, jailed, or sapped of the will to continue to resist. And with quiet restored, the Israelis had little incentive to leave the West Bank.

Belief in the possibility of a two-state outcome has been dwindling ever since. Jewish settlements in the West Bank steadily expand, as do the highways, electricity, water, sewage, and communications infrastructure that seamlessly connect them to Israel. Privately, diplomats whisper that they no longer think two states is possible. But they don’t yet have a plausible alternative to promote. So they keep repeating empty phrases they no longer believe in — there is “growing urgency” to “reverse negative developments” and “establish a political horizon” through the “resumption of a meaningful peace process,” because “a negotiated two-state outcome is the only way to achieve an enduring peace”—hoping that a new paradigm will emerge.

For the Palestinians, the two-state solution was never an ideal. It was a pragmatic accommodation with Zionism, the ideology at the root of Israel’s claim to the land and its refusal to allow non-Jewish refugees to return. The idea of partitioning Palestine into two states along the pre-1967 borders was an attempt to settle the Israeli-Palestinian conflict by pretending its main area of dispute was the occupation that began in 1967.

But the true heart of the conflict had always resided in 1948. Now, as the two-state outcome itself has come to be seen as impractical, the rationale for pragmatism has been further undermined. Growing numbers of Palestinians, especially among the youth, have started to return to the original ideals of the national movement.

In Gaza, on May 14, the eve of the national day of mourning for the Palestinian catastrophe, or nakba, of 1948, tens of thousands of Palestinians plan to take part in what has been named The Great March of Return. Over two-thirds of Gazans are refugees and descendants of refugees from towns and villages in Israel. Their aim is to cross the Gaza fence and implement the return to their lands that Israel and the international community have denied them.

Seventy years after Israel’s declaration of independence, the conflict appears to be returning to its roots. The Israeli government is demanding that Palestinians recognize the right of Jews to their own state in historic Palestine. The Palestinians are demanding the right to return home. The two goals cannot be reconciled. And the passing of time has done little to quell the yearning for them.

Sign up for Inside TIME. Be the first to see the new cover of TIME and get our most compelling stories delivered straight to your inbox. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.