Over the five years between the announcement of the dam proposal in 1978 and the axing of the plans in 1983, there was vigorous debate between the pro- and anti-dam lobbies, with large protests from both sides.

[3] The dispute became a federal issue the following March, when a campaign in the national print media, assisted by the pictures of photographer Peter Dombrovskis, helped bring down the government of Malcolm Fraser at the 1983 election.

However, the protest movement which had gathered to fight the construction of the Lake Pedder Dam earlier in the 1970s began to reassemble in response to the announcement.

From early 1981, archaeologists uncovered evidence of human habitation dating from about 15,000 years before present in caves which would be flooded if the dam were to be built.

[12] The ongoing crisis resulted in the replacement of Lowe as premier by Harry Holgate, a Labor politician who was markedly more supportive of the dam proposals.

Norm Sanders, an Australian Democrats MP and anti-dam campaigner, moved a no-confidence motion, and a state election was called for 15 May.

Bob Brown toured the country raising support for the anti-dam campaign, attempting to convince Liberal Prime Minister Malcolm Fraser to intervene and override the state legislation allowing the dam's construction.

British botanist and TV presenter Professor David Bellamy addressed 5,000[citation needed] people at a Melbourne rally.

By the end of 1982, any perception that "greenies" equated with hippies had been greatly challenged, for example in Sydney, Bob Brown and Bellamy addressed 500 people at a candle-lit dinner serenaded by string quartet,[15][16] ABC's classical music radio station featured a "Concert for the Franklin", and electronics entrepreneur Dick Smith committed to civil disobedience.

In the federal Lowe by-election in Sydney, March 1982, volunteers[17] at every polling booth encouraged voters to write "No Dams" on their ballot paper, and 9% did so.

On the same day, the UNESCO committee in Paris was due to list the Tasmanian wild rivers as a World Heritage site.

[22] This resulted in the subsequent proclamation of the Tasmanian Wilderness World Heritage Area, which covered both the Franklin and Gordon Rivers.

While the blockade was ongoing, Norm Sanders resigned from the Tasmanian House of Assembly to contest a seat in the Australian Senate.

The state government made things difficult for the protesters, passing several laws and enforcing special bail conditions for those arrested.

The author John Marsden, after being arrested at the blockade, was placed in the maximum security division of Risdon Prison for a week as there was nowhere else to hold him.

Folk rock singer Shane Howard from the band Goanna wrote "Let the Franklin Flow",[24][25] and released it in April 1983.

Hawke's government first passed regulations under the existing National Parks and Wildlife Conservation Act 1975, and then passed the World Heritage Properties Conservation Act 1983, which prohibited Franklin River dam-related clearing, excavation and building activities that had been authorised by Tasmanian state legislation.

They claimed that as the right to legislate for the environment was not named in the Constitution, and was thus a residual power held by the states, that the World Heritage Properties Conservation Act 1983 was unconstitutional.

The federal government, however, claimed (successfully) that they had the right to do so, under the 'external affairs' provision of the Constitution as, by passing legislation blocking the dam's construction, they were fulfilling their responsibilities under an international treaty (the UNESCO Convention for the Protection of the World Cultural and Natural Heritage, Australia having signed and ratified that convention and the Franklin River having been listed on it).

On 1 July 1983, in a landmark decision, the High Court on circuit in Brisbane ruled by a vote of 4 to 3 in the federal government's favour.

This ruling gave the federal government the power to legislate on any issue if necessary to enforce an international treaty and has been the subject of controversy ever since.

Justice Lionel Murphy wrote most broadly of the Franklin Dam decision's broader environmental and social implications in terms of the UNESCO Convention's common heritage of humanity principle, stating that "The preservation of the world's heritage must not be looked at in isolation but as part of the co-operation between nations which is calculated to achieve intellectual and moral solidarity of mankind and so reinforce the bonds between people which promote peace and displace those of narrow nationalism and alienation which promote war...[t]he encouragement of people to think internationally, to regard the culture of their own country as part of world culture, to conceive a physical, spiritual and intellectual world heritage, is important in the endeavour to avoid the destruction of humanity.