Prime Minister Ehud Olmert's reported gestures to Syria have harmed Defense Minister Ehud Barak in the battle between the two men over votes from the center-left in the next general election, a senior Labor official said Thursday. Syria was the only issue that had allowed Barak to differentiate himself from Olmert, who had positioned himself to the Left of Barak on the Palestinian issue but had refrained from pursuing the Syrian track until recently, and even told the haredi newspaper Mishpacha, "As long as I am prime minister, the Golan will stay in our hands." Barak had been seen as the government's main proponent of talks with Damascus until this week's reports. "Olmert knows he cannot get votes from the center-right of the political map, so he is trying to prove to people between Meretz and Labor that he is the hope for reaching peace with both the Palestinians and Syria," the senior Labor official said. "There is no doubt that this move helped Olmert and hurt Barak politically." In March, Barak and his loyalists discussed running on the Syrian issue in the next election to highlight the differences between him and Olmert. "Focusing on Syria shows people who think that Olmert leads the peace camp that Barak is willing to take a risk for peace that Olmert is not," a Barak supporter said following those deliberations last month. "It also reminds people that the man who took a risk for peace with [Palestinian Authority head Yasser] Arafat was Barak, not Olmert." In the same deliberations, Barak and his loyalists said that the other possible issue that could differentiate Olmert from Barak would be if Barak would come out in support of releasing Fatah terrorist Marwan Barghouti from prison. Barak's close ally, National Infrastructures Minister Binyamin Ben-Eliezer, has championed Barghouti's release, but Barak has refrained from speaking on the issue because of the sensitivity of his job as defense minister and because he did not want to be seen as undermining the diplomatic process with PA President Mahmoud Abbas. It is possible that the likelihood of Barak eventually endorsing Barghouti's release increased when Olmert took away Barak's advantage on the Syrian issue. A source close to the prime minister said his decision to pursue negotiations with Syrian President Bashar Assad had nothing to do with his own political situation. "Olmert, like many of his predecessors, is merely examining the possibility of relations with Syria," the source said. "I would not look too far into the possibility of there being immediate results to the contacts with Syria, and I would certainly rule out that he is doing it to advance himself politically." The prime minister will face a challenge within Kadima on the Syrian issue when the Knesset reconvenes on May 18. Knesset House Committee Chairman David Tal of Kadima said he would convene his committee to advance a bill requiring a national referendum before any concessions are made to Syria on the Golan Heights. The bill, originally sponsored by Olmert's erstwhile foe in Kadima, former MK Avigdor Yitzhaki, has already passed a preliminary reading in the Knesset plenum. Tal said the bill had a good chance of approval, because it had wide support inside the coalition. Pensioners Party Chairman Rafi Eitan told Army Radio on Thursday that he would support the legislation. "If the time comes to give up the Golan, it should be brought as a referendum," Eitan said. "Such a step needs the support of the people. For me, giving up the Golan would be no different than giving up Kfar Saba. In the current situation, with the way Syria is behaving toward Lebanon and Iraq, it is forbidden to give up any of the Golan." But other MKs expressed caution on Thursday about the possibility of holding referenda in Israel for the first time. They said that holding a referendum on the Golan could open up a Pandora's box. Meretz leader Haim Oron told Israel Radio that if a referendum were held on the fate of the Golan, he would insist on a referendum on legalizing the sale of hametz during Pessah. Channel 2 reported Thursday night that some 70 MKs opposed withdrawing from the Golan, including almost half the lawmakers in Kadima. The list included some of Olmert's closest allies, such as Construction and Housing Minister Ze'ev Boim and MK Avraham Hirchson, who recently bought a house on the Golan.