A showdown is brewing in Washington over how the number of Palestinian Arab refugees is being counted, and it could be explosive. This is because numerical accuracy would undermine claims by the Palestinians that before long, if their demands are not granted, Jews will become a demographic minority between the Jordan River and the Mediterranean.

Arithmetical distortions by the Palestinian Arabs have mesmerized the United Nations, the State Department, NGOs whose identities derive from the Palestinian determination to be permanent victims, and Israeli politicians who eagerly incorporate Palestinian misinformation into their critique of Jewish settlements.

Upon completion of the first Palestinian census 15 years ago, the head of the Palestinian Central Bureau of Statistics conceded that it was “a civil intifada,” a demographic weapon against Israel that specifically targeted Jewish settlers. Last December the Bureau fired its guns once again, reporting that 2.6 million Palestinian Arabs inhabit Judea and Samaria, the biblical homeland of the Jewish people where more than 300,000 Israelis now live.

These inflated Palestinian numbers have been sharply challenged by Israeli demographer Yoram Ettinger, who labels them “demographic misrepresentations.” According to his data the PCBS has inflated the number of West Bank Arabs (actually 1.6 million) by 66%. Its estimate includes more than 400,000 overseas residents (a violation of international demographic standards), a “double count” of 240,000 Jerusalem Arabs, and under-reported Palestinian emigration.

Mr. Ettinger’s calculations indicate that Jews now make up 17% of the total population of the West Bank (while Arabs make up 20% of the Israeli population.) Between the Jordan and Mediterranean, two-thirds of the population is Jewish. Since 1995 Arab birth rates have stabilized while annual Jewish births have risen significantly. “There is a demographic problem,” Mr. Ettinger concedes, “but there is no demographic machete at the throat of the Jewish state.”

The flip-side of Palestinian demographic distortion is the persistent claim that 5 million homeless “refugees,” scattered throughout the world, enjoy the right of return to their lost homeland (Israel). The United Nations Relief and Works Agency was established in 1948 to provide support for the 750,000 Palestinians (some 30,000 of whom are still living) who lost their homes during Israel’s war of independence in 1948 and either chose to leave or were forced out. It has fed Palestinian grievances by deciding that all 5 million descendants of the original refugees are also eligible for support, now amounting to $1.23 billion annually.

The State Department has long been complicit in this charade. Senator Kirk, a Republican of Illinois, recently inserted in the State Department funding bill an amendment to require the department to provide Congress with the number of Palestinians physically displaced from their homes in 1948, and the number of their descendants administered by UNRWA.

In a letter to the Senate Foreign Relations Committee, Deputy Secretary of State Thomas Nides responded that Kirk’s “proposed amendment would be viewed around the world as the United States acting to prejudge and determine the outcome of this sensitive issue.” The last thing the State Department seems to want is for a decision about American aid to Palestinians, now $400 million annually, to be based on documented evidence of refugee status. This could be embarassing, especially when the Palestinian Authority spends more than $5 million monthly in American funding for the salaries it pays to 5,500 convicted and alleged terrorists imprisoned in Israel

The Kirk amendment has been approved by the Senate Appropriations Committee. But even if Congress ratifies it (unlikely) and President Obama does not veto it (unimaginable), final funding decisions will still rest with the UN.

Human rights organizations compete to provide aid to Palestinians living under Israeli “occupation.” The New Israel Fund, B’tselem, Peace Now, and the European Instrument for Democracy and Human Rights, among an array of like-minded groups, would have many fewer causes to pursue – and to sustain their own organizations – if Palestinians were removed from their roster of victims. As Seth Frantzman wrote in the Jerusalem Post, “the occupation is their raison d’etre and without it they cannot exist.”

The Palestinian scam goes even deeper. Even if there is a State of Palestine, the Palestinian ambassador to Lebanon recently acknowledged, Palestinians – including those living in refugee camps inside the new state – “are still refugees. They will not be considered citizens.” Why not? Because they would then forfeit their “right of return” to Israel. “Even a [Palestinian] state accepted as a member of the United Nations,” he insisted, “is not the end of the conflict.”

Ambassador Abdullah failed to mention that when, in 1988, the Hashemite monarch, King Hussein, relinquished claims to the West Bank, he terminated Jordanian citizenship for the Palestinians who lived there, leaving them stateless – and ripe for plucking by human rights agencies for their own anti-Zionist political agendas.

For some humanitarians, it seems, the conflict can only end once Palestine replaces Israel. Palestinian arithmetic is designed to hasten that day.

Mr. Auerbach, a professor of history emeritus at Wellesley, is the author, most recently, of “Against the Grain: A Historian’s Journey,” published by Quid Pro Books.