Before I left for the Your Party rally in Manchester, I carefully looked at myself in the mirror. My Star of David necklace and rings with Hebrew etchings were off, and I ran through, yet again, the alternative name and identity I had prepared in case anyone asked. After all, it’s not every day that a Jewish-Israeli woman sneaks alone into the meeting of a party that proudly described as the ‘only anti-Zionist party in the entire country.’ So I tried to blend in. All I had to do was temporarily become a useful idiot: I enthusiastically collected leaflets from...