Foreign Minister Tzipi Livni used a cryptic expression from the Talmud to fight back against a fierce attack unleashed against her on Wednesday by Defense Minister Ehud Barak. Barak has been attacking Livni all week after deciding that he needed to get a head start in his effort to bring down the front-runner for the Kadima leadership ahead of a race for the premiership in which they will likely face off. The attacks culminated Wednesday with an Army Radio interview in which Barak called Livni by her full first name of Tzipora, and questioned her ability to make decisions. Asked about Barak's statements following a speech for the Reut organization at Latrun, Livni told The Jerusalem Post, "As it says in the Talmud, 'Don't try to explain that which is beyond you.'" The quote comes from the Talmud tractate Hagiga, which quotes from the apocryphal book of Ben Sirah, and she used it to imply sarcastically that she was unworthy of responding to Barak. Later in a Kadima event in Hadera, Livni added that Barak was "too little for Kadima" to warrant responding to him. Barak referred in his interview to US presidential candidate Hillary Clinton's commercial that warned of her rival Barack Obama's unpreparedness for receiving a phone call at 3 a.m. requiring an immediate and fateful decision. "The foreign minister, with her background as it is, is not built to make decisions, not at three in the morning and not at three in the afternoon," Barak said. "Being in the room when decisions are made does not make you fit and ready to make them." Barak said Livni's recent statements about UN Security Council Resolution 1701 that ended the Second Lebanon War in 2006 being her top achievement raised questions about her judgment, because it was obvious to security authorities that the resolution was a failure. Turning his attention to Kadima as a whole, the Labor leader called the party a "refugee camp" and predicted that it would only last one term. "People will realize that Kadima brought us the repercussions of the disengagement, the Second Lebanon War and a series of embarrassing scandals that the heads of Kadima didn't even protest," Barak said. "In the next election, [Likud chairman Binyamin] Netanyahu and I will compete against each other at the heads of the two ruling parties." Livni's main competition in the Kadima leadership race, Transportation Minister Shaul Mofaz, speaking at the same Kadima event in Hadera, made a point of defending her. Barak should not have attacked her personally and Livni should respond with "restraint and cool-headedness," Mofaz said. A Kadima spokesman responded in a harshly-worded statement that "it is clear to everyone that the leader of the bankrupt Labor Party has become hysterical and is on the verge of collapse, because he realizes that his party has become irrelevant." Labor responded with its own statement accusing Kadima leaders who attacked Barak of "hallucinating" due to the dire situation in Kadima. "I see that Mr. Security [referring to Barak] is panicking, because of Livni's growing popularity," said Finance Minister Ronnie Bar-On, who is one of Livni's top supporters in next month's primary. Livni picked up a key endorsement on Wednesday from Kadima MK Tzahi Hanegbi, who accused Barak of displaying chauvinism in his attack on Livni. Hanegbi said he decided to support Livni, both because of her merits and because he was concerned that Mofaz would move Kadima too far to the right. "I have respect for all four candidates but I had to go with my instinct that led me to join [then-prime minister Ariel] Sharon in Kadima," Hanegbi said. "Livni, like Sharon, represents the idea that the good of Israel requires that the country be led by a centrist party that can bring together people from across the political spectrum in a Zionist consensus that avoids the extremes on diplomatic and security issues." Hanegbi endorsed Livni despite the support for Mofaz of many of the key Kadima activists who are closest to him. Kadima officials said Hanegbi told the activists that he did not expect them to follow him to the Livni camp and that therefore the boost he would provide the foreign minister's campaign was merely psychological. A Likud MK accused Hanegbi of "selling his soul to a devil in Livni, who is more left-wing than Meretz and who has proven that she has no red lines in what she is willing to give the Palestinians." MK Yohanan Plesner became the ninth MK to endorse Livni later on Wednesday, and helped give her a lead in the faction over Mofaz, who has the support of six lawmakers. Several top Kadima MKs remain on the fence, including Vice Premier Haim Ramon, Negev and Galilee Development Minister Ya'acov Edri and Immigrant Absorption Minister Eli Aflalo. Aflalo's support is especially important, because he has registered more than 5,000 Kadima members, whom he says will vote for whoever he endorses. He made a deal with MK Shai Hermesh, who controls Kadima's kibbutz and moshav sector, to support the same candidate and work together. "Eli has no doubt that whoever he supports will win," a source close to Aflalo said. Government officials, meanwhile, indicated that the leaking of a letter blasting Barak from Ambassador to the US Sallai Meridor was linked to the Livni-Barak flare-up. Channel 2 reported that Meridor, in the letter, said that Barak's failure to include him or embassy officials in the defense minister's meetings earlier in the month with US Defense Secretary Robert Gates and National Security Adviser Stephen Hadley had "damaged the ability of official representatives in Washington" to do their jobs. "You harmed Israel's ability to influence events in Washington," Meridor was quoted as having written. "It is a shame you have chosen to do so. I am sorry that is the way things work in our country." Copies of the letter were sent to Barak, Prime Minister Ehud Olmert and Livni. A spokesman for Barak dismissed the letter as "spiteful" and said that Meridor was present at Barak's meeting with Vice President Dick Cheney and Secretary of State Condoleezza Rice. He said the Americans requested that the other two meetings be limited to a bare minimum, and it was decided to take a member of Israel's National Security Council to the meeting with Hadley, and Barak's director-general to his meeting with Gates. Herb Keinon contributed to this report.