Between the nondescript ACT Legislative Assembly on the north side of Lake Burley Griffin, and the federal Parliament on the southside's Capital Hill, lies the High Court of Australia. It is here that the ACT and federal governments will fight over marriage equality.

Last week federal Attorney-General George Brandis took the unusual step of announcing an intention to challenge legislation that had not yet been passed: the ACT’s proposed same-sex marriage laws. Brandis’ announcement was the latest shot taken in a Territory / Commonwealth battle that began with the ACT's declaration that it would move on marriage equality, less than a week after September’s federal election.