The case was an important decision about the implied freedom of political communication in the Australian Constitution in which the majority held that provisions of the Tasmanian Protesters Act[2] were invalid as a burden on the implied freedom of political communication in a way that was not reasonably appropriate and adapted, or proportionate, to the legitimate purpose of protecting businesses and their operations.

[8] Bob Brown, the former parliamentary leader of the Greens, had a long history with the Tasmanian environmental movement, being involved in the 1972 campaign to save Lake Pedder[3] and blockading the Franklin Dam project in 1982, for which he spent 19 days in prison.

[1]: para 16  Despite the charges being dropped, Brown and Hoyt sought to challenge the validity of the Protesters Act in the High Court.

In applying the decision in Lange v Australian Broadcasting Corporation,[12] the High Court had to consider three issues:Six of the judges held that the law was a burden on political communication.

[1]: para 95 The basis of the dissent by Edelman J was that the conduct was already prohibited, within his construction of the act; which through the principle of legality, he reached independently of the 6 other judges.

[3] Gageler J agreed with the result but gave very different reasons, disagreeing that the proper test was proportionality.

The practical difficulty he found with the provisions was not that they were vague or imprecise, but that the practical ability of a person to express a particular political view was significantly burdened by the broad discretion conferred on police officers, based on the formation of a reasonable belief, emphasising "the breadth and severity of the consequences".

[16]The use of proportionality as a test of constitutional validity starts from the perspective that the freedom of political communication is not unlimited, that the various Australian parliaments may make valid laws that affect the exercise of political communication, and that it is generally up to the parliament to decide whether it should make that value judgment.