Kadima's "Confinement Bill," which would deter rebel MKs from breaking off from the party, is expected to pass a ministerial vote on Sunday.The bill was proposed by MK Yuval Zellner (Kadima), a staunch ally of party chairman and Vice Premier Shaul Mofaz, in order to cancel the so-called "Mofaz Law," which made seven the minimum number of MKs that can split from a faction, regardless of its size. The law is named after Mofaz due to rumors that he was leaving Kadima, though the legislation was opposed by its namesake.Should Zellner's bill be approved by the Ministerial Committee for Legislation and pass Knesset votes, the previous law, which required one-third of a faction for a split, will be restored.Kadima sources say that several of the party's MKs, including Robert Tibayev, Shlomo Molla, Orit Zuarets, Nino Abesadze and others who backed former party leader Tzipi Livni, are considering leaving Kadima. On Wednesday, Tibayev, Abesadze and MK Yoel Hasson (Kadima) voted against the coalition, in favor of a bill criminalizing discrimination against women.Tibayev sent faction chairwoman Dalia Itzik letter on Thursday, asking her to request that Zellner wait for a faction meeting on the bill before it is brought to a ministerial vote."As you know, in the last faction meeting on May 14, several MKs, including myself, expressed opposition to the bill," Tibayev wrote.Zellner defended his bill on Friday, saying that it "sends a clear message – Kadima is one and united, and will stay that way."When asked why legislation is necessary if Kadima is united, Zellner explained that MKs who want to break off from the party may still do so, and the bill is only a matter of funding."I won't stop whoever wants to leave," he said. "This will prevent political blackmail, by not allowing groups of MKs to take money from the party according to their own agenda."According to Zellner, his bill will increase political and governmental stability, and the "Mofaz Law" was unnecessary to begin with.