Johannesburg - Western Cape Premier Helen Zille must be “dealt with” for her praise of colonialism and expelled from the party, several DA leaders said on Wednesday.They believed that how the party handled her defence of colonialism would test the party’s commitment to non-racialism.The leaders, who spoke to News24 on condition of anonymity, include members of the DA’s federal council. They expressed concern over the reputational damage she had caused the party.Her continuing defence of her views, in an article published by the Daily Maverick on Monday, was a declaration of war with party leader Mmusi Maimane.On Thursday, Zille posted a series of tweets on “lessons” learnt from a visit to Singapore.“For those claiming legacy of colonialism was ONLY negative, think of our independent judiciary, transport infrastructure, piped water etc,” she wrote.Maimane was seen as Zille’s protégé. He ascended to the position of DA leader with her backing at the party’s 2015 elective conference.The controversy had seen those who opposed Maimane at the congress rallying behind him and accusing Zille of trying to “rule from the grave”.The party leaders praised Maimane for referring Zille to a disciplinary hearing and publicly distancing the DA from her views.Her Daily Maverick article, entitled "From the Inside: Lessons from Singapore" was seen as a direct challenge to Maimane when he had already initiated a disciplinary process.“Instead of backing off and allowing processes to unfold she takes on Mmusi Maimane, completely undermines him in public. Remember she raised him and is now trying to show him that without her he is nothing,” one leader said.'We have to deal with her'They compared the spat to the conflict Zille had with former DA parliamentary leader Lindiwe Mazibuko.“I made you, I can break you. Mmusi is being challenged because he dared to take action – same thing with Lindiwe,” one provincial leader said.Another leader in Gauteng said Maimane had to see the disciplinary process through. Zille had to face a stern sanction. The DA’s federal executive could accept the findings of the disciplinary panel, or could increase or reduce the sanction.“If there was remorse, where she admitted she flopped, it would be one thing. But she is not sorry. She continues to defend it using freedom of speech. That was her intimidating him,” one leader said.The leaders believed Zille had been let off the hook on several occasions.She had courted controversy for tweets including: "Why is it ok to racially classify people for jobs, but not to identify people at a table by their race?"In 2012, she called pupils who moved to the Western Cape from the Eastern Cape in search of a better education, refugees.“This is the cherry on top of the recklessness she has always displayed. Now we have to deal with her or have a fallout,” a leader in the party's federal council said.Impact for 2019The biggest concern is the impact on the party’s campaign for 2019. The DA believed it could dislodge the ANC in Gauteng and grow support in other provinces, especially in urban centers.A lenient sanction would bolster the ANC’s claim that the party was one of white racists where black people acted as stooges.“It’s horrible for blacks within the party always being called tea girls, gardeners, defenders of white monopoly capital, and puppets. I am excited that she screwed up so big that it can’t be ignored,” a senior member said.Another said they were concerned about the reputational damage ahead of the elections.“It has already had an impact on what we are building that the DA is a non-racial party. Her utterances have taken us back.”The leaders wanted the party to be consistent, following the censure of MP Dianne Kohler Barnard.Her party membership was terminated at the end of October 2015 after she shared journalist Paul Kirk's Facebook post."Please come back PW Botha - you were far more honest than any of these [African National Congress] rogues, and you provided a far better service to the public," it read.At a disciplinary hearing, she pleaded guilty to breaching the party's social media policy and bringing it into disrepute.Her expulsion was lifted following an appeal. The party decided to keep her in her position until the end of the fifth Parliament, on condition that she not be found guilty of any transgressions during that period.A Gauteng leader warned that if the party was too lenient on Zille, it would send the message that members could say what they wanted, which would weaken Maimane’s leadership.