It is appropriate that U.S. Secretary of State John Kerry is in Jerusalem this week, exactly 65 years to the day when pre-state Zionist troops massacred some 100 unarmed Palestinian men, women and children in the Palestinian Arab village of Deir Yassin, west of Jerusalem. That was five weeks before the formal end of the British Mandate, the declaration of a Zionist Israeli state on May 15, 1948, and subsequent all-out warfare.

The timing of Kerry’s visit is “appropriate” because of three pivotal factors that he should consider if he is at all serious about making a new diplomatic push for Palestinian-Israeli negotiations that could form the centerpiece of a broader Arab-Israeli peacemaking process.

These three factors are, first, that any successful American mediation must assign equal emotional validity and political weight to the sentiments of both Israelis and Palestinians, without favoritism.

Second, the heart and soul of the Palestinian national struggle does not revolve mainly around creating a state in the lands occupied in 1967, but rather on resolving the dominant issue of the refugee status, exile and dispersal of the Palestinians that started in 1947-48 and has continued ever since. A small West Bank-Gaza state is part of that larger resolution of the conflict that is mainly anchored in ending this refugee status politically, emotionally and territorially.

And third, the single most poignant and politically symbolic incident in our status as refugees and exiles is the massacre of Deir Yassin, which Palestinians remember and commemorate every year, because it captures the most important dimensions of their 65-year-old national trauma.

Historians from Israel, Palestine and other countries have documented the Deir Yassin massacre as meticulously as any historical incident can be documented. Both sides disagree on some key issues, especially the Zionist armed groups’ motivation for the massacre. Palestinians see Deir Yassin as part of a broader, deliberate and well-executed campaign of savage atrocities to forcibly evict Palestinians from the territory that would become Israel – an example of what the world now calls “ethnic cleansing.”

Zionists, on the other hand, say their forces were defending themselves, and if any atrocities occurred they were singular exceptions committed by local militants, and not part of an organized campaign.

Regardless of what Palestinians, Israelis or others feel, the important thing for Kerry to appreciate is that Deir Yassin and the trauma of the refugees and that of exile are as central to the Palestinian psyche as the idea of Israel’s “right to exist” as a “Jewish state and homeland” is to many Jews, and to all Zionists. Acknowledging both those historical narratives and psychological realities as having equal validity is absolutely central to any external mediator’s efforts to succeed in resolving this conflict.

Washington’s mediation has consistently failed for decades precisely because it did not give Palestinian and Israeli rights equal weight. As the U.S. embarks on yet another attempt to foster Israeli-Palestinian peace negotiations, Kerry should take advantage of being in Jerusalem on the 65th anniversary of the Deir Yassin massacre to ponder these issues more diligently.

He will echo his president’s moving commitment to securing the Jewish people’s state and homeland, and to feeling the pain of the Palestinians who yearn for a normal life. But that skewed dichotomy will only fail again, as it has many times in the past, because it equates the rock-solid certainty of Zionist statehood with only the soft perceptions of Palestinian yearning. It perpetuates the chronic imbalances in acknowledging the two sides’ needs and rights.

I hope one day Kerry will muster the moral courage and mediator’s acumen to actually visit – or even just drive by – the sites of Deir Yassin, or Lifta, or Maliha, or any of the other dozens of former Palestinian villages and West Jerusalem Arab neighborhoods whose 28,000 Palestinian inhabitants were largely displaced or expelled, mostly before Israel’s declaration of statehood in mid-May 1948. For Palestinians, the key to understanding the Palestinian psyche and the political realities shaping the contours of an acceptable permanent peace agreement with Israel rests firmly on resolving the wrongs and the crimes that resulted in our becoming refugees and exiles. These acts began in November 1947, and were committed by Zionist armed groups, militias, and ethnic-cleansing units.

Kerry or anyone else who wishes to understand this issue should take advantage of an offer by the Institute for Palestine Studies and the Journal of Palestine Studies to make available, free of charge for this week only, the compelling short article, “The De-Arabization of Jerusalem 1947-50,” by Nathan Krystall. The article describes the context surrounding the progressive depopulation of Arabs in Jerusalem in that pivotal period.

As we count another year, the Palestinian exile is now 65 years old, which is some seven years longer than the ancient Jewish exile in Babylon in the mid-sixth century B.C. We Palestinians remember Deir Yassin much like Zionists remember their forcible exile in Babylon. Mediators who recognize this pivotal reality can foster blessed justice and peace, and make history.