With the high court to decide on the legality of the same-sex marriage postal survey and the dual-citizenship cloud hanging over an increasing number of MPs, Katharine Murphy talks to constitutional law expert George Williams from the University of New South Wales. He says that traditionally the high court has been very clear about these issues and will likely declare ministers ineligible to stand. What can we learn from the precedents in the high court and how are its members likely to view these cases?