On Tuesday, Palestinians mark “Nakba Day,” translated as “the Catastrophe,” or “Disaster.”Celebrated annually on May 15, it commemorates the founding of the State of Israel in 1948 and the subsequent displacement of an estimated 700,000 Palestinians who fled or were expelled from hundreds of Arab towns and villages in what was pre-state Israel.We can all agree that Palestinians did flee or were expelled, and most of those Arab villages and towns are no more. Where we disagree is why.What would have happened if, in March 1920, the Palestinian Arab Executive Committee hadn’t told the Mandatory Government: “Either us or the Zionists.There is no room for both elements struggling in the same area?” What if violence was not adopted by the Arab leadership, first in 1921, then in 1929 and again in 1936? What if in 1947, Arab leaders had not rejected the UN partition resolution that would have given them a state? What if the response to David Ben-Gurion’s announcement on May 14 declaring the birth of the State of Israel had not been met by the armies of the Arab League invading Israel within hours? The answer is that there would have been not one Arab refugee. There would have been two states living side by side. Moreover, we can also agree that May 15, 1948, was a catastrophe. Where we disagree is why.It is a catastrophe because of what might have been.Imagine if those two states had been partners in a new venture: two democratic states in the middle of the Middle East, forging not only a bond built on trust and confidence but establishing a basis for future generations to grow old together, providing an example for other states in the Levant to emulate.To be clear: One cannot blame the Palestinian people.It is their leadership – today no less than in 1921 – that has incited, used and abused them, and fed them with lies. Jews too were refugees starting in 1948, displaced in the hundreds of thousands from a dozen countries across the Middle East. But unlike Palestinian refugees, Jews ejected from Arab countries were not told to keep believing they would return and reclaim their lost homes. Nor were they kept in refugee camps for decades, or denied the right to become citizens of the country that took them in.It is within the power of the Palestinians to move forward, and the time is now. What appears to them to be a one-sided maneuver by the president of the United States – to declare Jerusalem as Israel’s capital and move that country’s embassy there is not one-sided – it is the reality.Jerusalem is Israel’s capital. If you accept that Israel exists – that Israel is a state – then you have to accept Jerusalem as its capital. It was the Jewish capital more than 3,000 years ago and is again today. There is no other place that is, or ever was, or ever could be. If you don’t accept that Israel is a state, well then, what is there to talk about? Our dissolution? Is all of Jerusalem Israel’s capital? In the end, probably not. Not if we come to a resolution based on two states for two people with Jerusalem recognized as having historical and religious significance for both Israelis and Palestinians.As David Ben-Gurion read from the Declaration of the Establishment of the State of Israel on May 14, 1948: “We extend our hand to all neighboring states and their peoples in an offer of peace and good neighborliness, and appeal to them to establish bonds of cooperation and mutual help with the sovereign Jewish people settled in its own land. The State of Israel is prepared to do its share in a common effort for the advancement of the entire Middle East.”The plight of the Arab refugees was a catastrophe because – unlike the psychological injuries suffered by Jewish refugees that were allowed to heal – the Palestinians were fed a lie, the better with which to exploit them as political and propaganda tools against Israel.They were told that the clock would be turned back and reverse the trauma of what is now 70 years, and everyone would be allowed to go back to their original home.But that is not how the world is today. No one is going back to 1948. Once Palestinians stop believing that, the “Nakba” will start to come to an end and we can move forward.