Anti-nuclear public opinion played a huge role in setting the stage for this Act. In the years leading up to the Act, strong anti-nuclear opinions were mounting. Visits to New Zealand by United States navy ships caused publicity and protest. Anti-nuclear opinion was exacerbated with the sinking of the Greenpeace protest ship the Rainbow Warrior (1955) on 10 July 1985. Maire Leadbeater observed that New Zealand’s nuclear free policy and the resulting legislation demonstrated “how ordinary people created a movement that changed New Zealand’s foreign policy and identity as a nation”.