It's not a comfortable feeling when a terrible tragedy brings with it a rush of hope and even relief. But that's what I felt as I saw the flickering candles held by thousands of people who flocked to protest in Australian capital city spaces, towns and suburbs last Sunday night. Could the crushing blows that brutally ended the life of Reza Barati be a tipping point in asylum seeker politics in Australia?

I am not for a moment suggesting that the horrific events on Manus or news of 700 vigils would change the mind of a government determined to spread a message of harshness and horror abroad, or a Labor party that has dug themselves into a very deep and dirty ditch by reopening the offshore detention camps in 2012. But the question is: will the memory of a 23 year old asylum seeker lying dying from neck and head wounds and the knowledge that many more similar young men were attacked with sticks and knives do more than spark vigils?

Vigils are safe for all, and allow us to focus on loss and abuse in an undistracted way. I think this is also what Ryan Sheales intends on his website when he invites people to send picture of themselves saying "sorry" to asylum seekers – to start simply by focusing on the inhumanity of our actions.

There are those who dismiss vigils as an outpouring of emotion that makes people feel better. I don't agree, but it's true such protests are not enough. Nothing will change if the momentum behind the vigil dissipates. After all, as Chillout so correctly pointed out, in the midst of the crisis unaccompanied Hazara children were transferred to Nauru without loud protests.

Much does depend on the media maintaining its focus on the issue. It was disappointing that so many journalists bought the assumption that extreme punishment of survivors could be an appropriate solution to tragic losses at sea. They demanded of opponents to offshore detention: do you want people to drown? It was always an arrogant and false alternative, that blotted out a history of terrible hunger strikes, mental illness and deportations to death that eventually led the Labor party to suspend off shore detention camps.

It's not a question of shifting hardcore supporters of Abbott's savage policies. Even the middle ground will shift, only slowly. It's about australian citizens deciding to commit themselves to a campaign to close Nauru and Manus. It's important to remember that we don't need to build a movement – there already is one. The Refugee Action Coalition group, the Asylum Seeker Resource Centre, and other centres and faith based organisations that have never stopped campaigning on refugees' behalf. One of the most corrosive ideas is that committed activists are not part of the "ordinary people". Activists are students, unionists, nurses, consultants, business people, teachers, builders. A movement involves much more than marching with placards, although it usually includes that, too. People can find their own ways of building momentum.

Artists too are part of politics. As I am writing this, I received a letter written by five artists withdrawing from the Sydney Biennale, which is partly sponsored by Transfield, the big Australian company that is profiting from off shore detention. They write: "We see our participation in the Biennale as an active link in a chain of associations that leads to the abuse of human rights. For us, this is undeniable and indefensible." Moving from outrage to clear sighted analysis, they are organising exhibits, discussions and events that focus on the connection between corporations, arts and government detention policies that are part of what has been called vulture capitalism. If the companies and organisations that benefit from these policies were to withdraw, the detention centres would have to close.

My own protest memory is long. Reading about the Biennale boycott, I flashbacked to a packed UNSW Roundhouse in which we held a "teach –in" of discussions about the Vietnam war, followed by the Moratorium march of thousands of students which joined a massive rally at Sydney Town Hall in 1970. The Vietnam war protest movement was quite small at the beginning but gradually built momentum, infiltrating workplaces, schools the arts and churches as public opinion shifted.

I also remember our determined, smaller and targeted Women Behind Bars and Prisoner Action Group Campaigns that led to the release of two wrongly women and the closure of a dehumanising maximum security unit. We created a mock lounge room outside corrective services for a whole winter, occupied offices, dropped banners down the sides of buildings, stopped traffic on the harbour bridge – and even spray painted a cabinet room. There have been many other successful campaigns over the years – from the Franklin River blockade to more recent environmental victories – even if starting and sustaining them can be overwhelming.

Some historic marches, like the ones against the War on Iraq, did not change politicians' minds. Despite massive opposition, we went to war against all reason. But by being there, we bore witness to the fact that most Australians did not wish to invade Iraq. Even when governments won't listen, it's important to place on the record our opposition to crimes committed in our name. It can provide some acknowledgement and even hope to victims and others who resist and a record that citizens did not blindly follow.

Last week won't be a tipping point if we don't make it one. We need to turn from witness and sorrow with a resolve that matches our government's determination to punish and deceive. It's up to us.