The Australian Conservatives party senator Cory Bernardi has rallied the spirits of anti-same sex marriage campaigners, telling the national launch of the Coalition for Marriage’s no campaign that they are on the right side of legal and moral history and that is why they are being attacked.

Spearheading the launch at the International Convention Centre Sydney on Saturday evening, Bernardi warned the audience that if the Marriage Act was changed to include same-sex couples it would lead to “legal warfare” against supporters of traditional marriage.

His warning fitted with the tone of the event, which placed its focus on the flow-on effects of altering marriage.