 In April 2019, Katz said that JLM would be selective in campaigning for Labour candidates in future elections, saying "If you’re backing the leadership and the way they have handled antisemitism – then you are absolutely not going to get our support" and "If you clearly and consistently support us...then we will have your back".JLM said their members would not campaign for Lisa Forbes in the June 2019 Peterborough by-election after it was revealed she had liked a social media post of a video of children praying in solidarity with the victims of the Christchurch mosque shootings with accompanying text which commented that Theresa May had a 'Zionist slave masters agenda', and had expressed her 'enjoyment' in reading a thread which included a comment that Islamic State had been founded and funded by the CIA and Mossad.Forbes said that she had liked the video and the content of a long thread of posts and had not noticed the specific comments.