No poll can credibly predict the results of Tuesday's second-round Labor primary. Polls are a snapshot of the mood and motivations within a representative sample of the electorate. Since the makeup of the party's membership doesn't conform to any recognized demographic pattern, such a sample of Labor's 103,000 voters just doesn't exist. As the first-round results proved two weeks ago, a large proportion of party members vote not according to any ideological or political consideration, but simply out of allegiance to local bosses, tribal elders and union leaders, in turn connected to one of the power-brokers. These were active mainly on behalf of Ehud Barak and Amir Peretz, while Ami Ayalon, Ophir Paz-Pines and Danny Yatom got almost all their votes from "independent-minded" voters, mainly in large towns and kibbutzim. Now that we're down to the two finalists, and most of the Peretz camp has joined up with Ayalon against the common enemy Barak, the balance is that much more cynical. The victor will not be the most attractive candidate or the one voters feel has the best chance of winning the general election. He will be the one whose various captains and allies do the best job of calling in all favors and cajoling their people into the voting booths. It's not what Labor's grassroots want that matters, it's a simple question of mathematics and logistics. Which bloc is worth more votes? Is it Peretz's organization down south, together with Ghaleb Majadle's supporters in the Arab sector working for Peretz, or is it Binyamin Ben-Eliezer's Arab and Druse followers together with Shalom Simhon's moshavnikim? It might be argued that Barak is at a slight disadvantage here. Despite beating Ayalon by five percent in the first round, no major operator has joined him. Paz-Pines and Yatom might have announced they are supporting him, but their voters are unlikely to be swayed by this and are expected to make their own choices in the second round. In contrast, Ayalon may have received only 30% in the first round, but the Peretz voters are believed to be a disciplined group and could hand Ayalon the chairmanship. But there are still a number of wild cards. This is the first case of a second-round runoff in any primary vote ever to be held in Israel, and there is no way of knowing what proportion of members will make a second trip to the polls. What kind of voters will turn up again? Will it be the ideological free-thinkers, and will the organized members feel that they did their bit in the first round? Or perhaps the independents are fed up and will stay home, disgusted with the cynical style of party democracy, while the family and union members will be made to realize that voting is in their interest. Barak might yet have a new team member in Histadrut Labor Federation Secretary-General Opher Eini who, in recent months, has turned against his predecessor and mentor, Peretz, with a vengeance. It remains to be seen if Eini extends his enmity to the Peretz-backed Ayalon and puts his considerable influence and resources at Barak's disposal. It would be ironic if another Histadrut secretary-general were to decide the outcome of a Labor primary and complete Peretz's humiliation. Another endorsement of Barak is expected to have little effect on the results. Knesset member Shelly Yacimovich might have announced her last-minute support for him, but few of her fans in Labor's "social circle" are likely to follow her lead and vote for a man who embodies Netanyahu-style capitalism in their eyes. Her justification, that Barak has the necessary experience to beat Netanyahu in a general election, was especially lame: If that was any kind of motive, why did she support no-hoper Peretz in the first round? For Yacimovich, the endorsement of Barak has little to do with achieving any effect on the primary. It was, rather, a rite of passage to her own political independence. Having joined Labor a year and a half ago as Peretz's starry-eyed acolyte, going against him and supporting his arch-rival is her way of saying that she now stands on her own two feet. As she made quite clear, she isn't joining Barak's camp, or any other. She is now that rare creature, a totally independent Labor MK.