Israel news photo: Flash90
Kadima chairman Shaul Mofaz on Monday blasted Prime Minister Binyamin Netanyahu saying he was a failed leader.
"Kadima is returning to the opposition with its head held high… to prove just how badly you have failed," Mofaz said to Netanyahu during a speech in the Knesset.
"Your recent actions have proven that you don't have the leadership ability needed at this time," he added.
His comments come one week after the collapse of a short-lived unity government formed by Israel's two largest parties, Mofaz's Kadima and Netanyahu's Likud.
The unity government, unpopular with many Kadima MKs, collapsed amid a dispute over replacing the controversial Tal Law.
Netanyahu disbanded a contentious failed Kadima-led committee tasked with drafting a universal service law that would induct full time yeshiva students and Arab men into the military.
However, Mofaz's own grip on Kadima has begun to fail, leading to calls for his resignation.
On Monday, Kadima officials threatened four MKs who refused to leave the Netanyahu-led coalition with inelligibility in Israel's next elections. Israeli law allows a minimum of seven MK's to leave a party and form a new faction.
Kadima sent a letter to the Knesset House Committee which is set to discuss its request to declare the four as "secessionists."
"This is a clear case of withdrawal from a faction where Kadima MKs join the coalition in exchange for positions," Mofaz wrote, charging Netanyahu with "political bribery."
Likud responded, "Mofaz is now the chairman of a quarter faction. Even those who sat beside him don't believe his slogans. Everyone remembers what Mofaz seems to have forgotten – he's the one who approved the Tal Law, when he enthusiastically voted in its favor in 2007."
So-called Kadima "seccesstionist" MKs, Avraham Duan, Arie Bibi, Otniel Schneller and Yulia Shamalov-Berkovich could not be reached for comment.
Meanwhile, Labor party leader Shelly Yechimovich and Independence party leader Ehud Barak both offered disenfranchized Kadima MKs politcal refuge in their ranks.