It would be an understatement to say that this was not an easy week for the leaders of the three largest parties in Israel, Prime Minister Ehud Olmert, Defense Minister Amir Peretz and opposition leader Binyamin Netanyahu. Olmert and Peretz had to deal with a worsening security situation that tested their leadership. Netanyahu was forced to cancel the start of a national tour of confrontation line communities intended to emphasize the failures of disengagement and warn against the prospect of a withdrawal in the West Bank. On top of all that, the three leaders had to deal with headaches caused by the disgruntled would-be leaders in their own parties. MKs Matan Vilna'i in Labor and Silvan Shalom in Likud have been a thorn in the side of Peretz and Netanyahu for months. Construction and Housing Minister Meir Sheetrit joined the disgruntled duo when he unleashed a blistering attack on Olmert in an interview with The Jerusalem Post last week, which he intensified this week in the Hebrew press. In doing so, Sheetrit became the first Kadima politician to openly challenge Olmert's leadership and policies. Israel has no shortage of disgruntled politicians, from former prime minister Ehud Barak in Labor to Transportation Minister Shaul Mofaz in Kadima. But Vilna'i, Shalom and Sheetrit stand out, because they each feel that they were unfairly denied their rightful place at the helm of their parties and they are each warning that their leaders are taking them in the wrong direction. In Sheetrit's case, he briefly toyed with the idea of challenging Olmert for the Kadima leadership six months ago when former prime minister Ariel Sharon suffered his career-ending stroke. Now he is gearing up to challenge Olmert in the first-ever Kadima leadership primary, instructing political loyalists to sign up as many members as possible in Kadima's voter registration drive. Shalom believes that had he had more time to campaign against Netanyahu than the three-week short Likud primary, he would have beaten him and that he has enough support to win a rematch. Vilna'i has been critical of Peretz's methods of taking over Labor by using a party membership drive loaded with alleged improprieties. Since the March 28 election, Vilna'i and Shalom have been very vocal in criticizing Peretz and Netanyahu. Vilna'i said when the government was formed that Peretz did not have the skills to be defense minister and he repeated the charge following the Gilad Shalit kidnapping two weeks ago. Shalom has repeatedly called upon Netanyahu to quit due to the party's downfall from 40 seats to 12. "Both Silvan and I are at a political nadir and we are playing opposition roles," Vilna'i said. "I want to keep the values of historic Labor and return it to being a balanced, ruling party that with the right leadership can come back. I am not opposing Peretz for no reason. I am advancing what I believe in." Vilna'i rejected criticism alleging that his opposition was due to Peretz's decision to not appoint him a minister. He said that he has been consistently critical of Peretz from the start and decided against changing his tune to try to get a cabinet seat. Knowing full well that any criticism would be portrayed in the press as political opportunism, he decided it would be irresponsible to sit on the sidelines and remain silent. Unlike Vilna'i, who is considering allowing Peretz to delay the Labor leadership race, Shalom is eager for the Likud to hold a leadership primary as soon as possible. By next month, he believes he will have the minimum 600 signatures necessary for a Likud central committee vote on advancing the primary. "Some believe Bibi did great things, some believe he did awful things, but the people don't like him and he is unelectable," Shalom said, comparing Netanyahu's electoral prowess to that of Barak and Vice Premier Shimon Peres. "In sports, you replace the coach because you can't replace the players and the fans. The people want hope and they can't get it from Bibi. As long as he remains, he blocks the Likud's chances of recovery" Like Vilna'i, Shalom called his opposition to his party chairman's leadership "not personal." He said Netanyahu had to take responsibility for an election in which the party received 17,000 fewer votes than Shas and only 116 more than Israel Beiteinu. Shalom, Vilna'i and Sheetrit all believe that their political fortunes will rise again and that they will end up replacing the leader of their party ahead of the next general election. "I believe in my abilities and the ability of others to see them," Vilna'i said. "Likud members [who elect the party leader] realize now that they can't win an election with Bibi," Shalom said. "They are not blind or stupid."