Palestinian President Mahmud Abbas set up a showdown on Saturday with the governing Hamas movement by calling a referendum on a plan that would implicitly recognise Israel’s right to exist. The first-ever Palestinian referendum will take place on July 26, according to the decree signed by Abbas and read out to reporters by Tayeb Abdelrahim, secretary general of the Palestinian Authority. “The Palestinian people in Jerusalem, the West Bank and the Gaza Strip are asked to give their verdict in a referendum on July 26 on the document of national unity — the prisoners’ document,” Abbas said in the decree. The document calls for a national unity government, an end to attacks in Israel and the creation of a Palestinian state alongside Israel on land conquered by the Jewish state in 1967. “The idea of a referendum carries serious dangers for the unity of the Palestinian people and I fear that it may provoke an historic division that will take decades to overcome,” Prime Minister Ismail Haniya said in a letter to Abbas on Friday. Israeli Prime Minister Ehud Olmert has dismissed the referendum as “meaningless” and said it would have no bearing on the prospects of reviving the bilateral peace process.