The candidates in the May 28 Labor Party leadership race began campaigning in earnest this week by seeking new members to join the party and endorsements from Labor MKs. Former prime minister Ehud Barak spoke with Labor MKs this week and told them he intended to join the field of candidates that officially includes the incumbent, Defense Minister Amir Peretz, and MKs Ami Ayalon, Ophir Paz-Pines and Danny Yatom. Barak and Ayalon are hoping to get endorsements from MKs who have a wide following in the party. National Infrastructures Minister Binyamin Ben-Eliezer, who met with Ayalon on Thursday, is expected to endorse Barak and MK Avishay Braverman is expected to endorse Ayalon. Both Barak and Ayalon hope Paz-Pines will quit the race and endorse them. One Paz-Pines loyalist said it was more likely he would eventually endorse Ayalon with whom he co-sponsored an event in Tel Aviv on Wednesday and joined forces in maneuvers to set a date for the race that they both preferred. MK Matan Vilna'i is said to be leaning against running for Labor leader and his endorsement of Barak or Ayalon would give them a significant boost. Vilna'i still has thousands of supporters in the party, especially in the key kibbutz sector. Out of some 60,000 Labor members before the membership drive, approximately 15,000 were from kibbutzim. Barak and Ayalon are vying for support from the sector. Even Peretz, who has little support from kibbutzim, offered the vacant Science, Culture and Sport portfolio to Kibbutz Movement secretary Ze'ev Shore and the Kibbutz Movement's representative in the faction, MK Orit Noked, in return for an endorsement. Noked attended Peretz's campaign rally at the party's Tel Aviv headquarters on Wednesday by mistake, because she thought it was a party event. Labor activists reported receiving a dozen calls and text messages from supporters of Peretz, Ayalon and Paz-Pines asking them to attend different Hanukka lighting ceremonies that were held at the same time. One kibbutz official said it was likely the sector would endorse Barak, adding: "Yitzhak Rabin failed as prime minister before he came back and succeeded." The official said Ayalon would have a difficult time convincing the Kibbutz Movement to support him because he was still a freshman MK who lacked political experience. In an effort to raise funds, most of the candidates have already formed nonprofit organizations. State Comptroller Micha Lindenstrauss condemned Vice Premier Shimon Peres for taking advantage of a loophole in the law allowing the use of a nonprofit organization to raise funds when he ran for Labor leader. But Lindenstrauss ruled that it was not illegal.