Turnbull shows signs of being better at this than Abbott.
The United States has 56 governors of states and territories. It's difficult to get them all in the same room, let alone around the same table. Our state and territory leaders, on the other hand, gather regularly at the Council of Australian Governments. As a medium-sized federation we have an important advantage, and it's one we don't always fully appreciate: COAG is the perfect size to practise co-operative federalism.
As the final chairman of the now defunct COAG Reform Council, charged with monitoring the implementation of COAG agreements, I saw the value of co-operative efforts between state and federal governments in areas as diverse as health, education, homelessness and Indigenous affairs. 
When the Abbott government in 2014 withdrew $80 billion in proposed funding to the states and territories, goodwill between COAG partners took a blow. We badly need a
co-operative approach today.
Australia faces many challenges: "wicked" problems ranging from the terrorism threat to a health budget shortfall in the order of $35 billion. There is almost no problem that can be fixed by one level of government alone. Moreover, many of the challenges call for preventive responses; the most obvious being the rapid rise of chronic but preventable diseases such as type 2 diabetes and heart disease.
Co-operation is what makes prevention possible: we can co-operate to find solutions now, or we can fight about the problems later, when they will be much worse and much more expensive to fix.
Prime Minister Malcolm Turnbull has shown signs of being a more consultative COAG participant than his predecessor, and that's a good thing.
In my experience, three steps are needed to gain the full benefits of a
co-operative federalism:
First, leadership. Someone needs to propose a way forward, back it with evidence and sell it to their counterparts around the COAG table.
But leadership doesn't have to come from the top. Under premier Steve Bracks, Victoria pushed for a big new effort in building human capital, and this eventually took the form of an important new National Reform Agenda at a time when leadership at the federal level was waning.
There were some signs of leadership emerging at this month's COAG meeting - South Australian Premier Jay Weatherill, for example, proposed a new tax arrangement whereby revenue raised by an increase in the GST would remain with the Commonwealth, while the states would receive a share of income tax. It remains to be seen whether South Australia or any other state or territory will have the ability to convince their counterparts of a way through on tax reform.
The second step towards a successful co-operative federalism is jurisdictional flexibility. This means that, where possible, states and territories should be left to find their own way to common goals. This happened under the National Reform Agenda, and before that under Paul Keating's National Competition Policy.
It's not possible on every issue (tax reform is an obvious example where a uniform approach is necessary) but it could work well in areas such as preventive health. States should adopt a common goal - say, a 5 per cent reduction in the incidence of type 2 diabetes in low socio-economic areas - and find their own ways to get there based on local needs and circumstances. Successful policies can then be replicated by other states, and unsuccessful ones avoided.
Room for experimentation is one of the great advantages of a federal system; it's why the Americans call their states the "laboratories of democracy". Given Malcolm Turnbull's recognition of the importance of innovation, he should be the first to want to exploit this potential in our federal system.
The final step to a successful co-operative federalism can be summed up as "rewards for results".
This month's COAG agreed to develop "a new competition reform agreement", drawing on the Harper Competition Policy Review. This would "include the potential for productivity payments for delivery of reforms".
This is a step in the right direction. When the COAG Reform Council presented its final report to government on the progress of the COAG Reform Agenda (2008-13), we noted that "even relatively small reward payments have been effective in encouraging reform". After all, it's only fair: if the hard work of reform is done, the benefits should be shared. And it works both ways: the fact that the federal government will take most of the political pain of any increase in the GST means it will need to receive some of the gains of a tax that has been, up until now, directed to the states.
There was another very positive agreement at the most recent COAG: based on Queensland's suggestion, there will be a national summit on domestic violence in late 2016. This highlights one of the benefits of federalism: 10 heads really are better than one.
More importantly, the prospect of a national approach to reducing violence against women and children reminds us of what's really important when we get co-operative federalism right: the difference it can make to people's daily lives.
John Brumby is a former Labor premier of Victoria. His book, The Long Haul: Lessons from Public Life, was published in   November by MUP.