The near-absence of foreign affairs from the election campaign has been much criticised in recent weeks. At a time when global security is profoundly imperilled, with Russia expansionist and Isis rampant, our leaders have had little to say about this most momentous of subjects.

Ed Miliband will seek to redress this tomorrow when he delivers his first set-piece speech on foreign affairs as Labour leader. Given the centrality of the Iraq war to his 2010 campaign, and the degree of global instability, many in the party have long lamented his relative silence on the subject. For Miliband, after the significant improvement in his personal ratings, it is another chance to assert his credentials as an alternative prime minister.

Speaking at Chatham House, he will accuse David Cameron of presiding over the "biggest loss of influence for our country in a generation" through "small-minded isolationism". By way of an alternative, he will promise "a genuine and hard-headed multilateralism with our values at its core". In reference to the Iraq war, he will say: "We must also learn the lessons of previous interventions. These are the vital lessons of our recent past and I will not forget them. Legitimate interventions must be supported by international, regional and local players, carried out with a clearly defined strategy, as well as include a comprehensive transition and post conflict strategy."

The "Miliband doctrine", as it will inevitably be dubbed, is defined as "A government that is outward looking, not inward looking; optimistic about our role, not pessimistic; always learning the lessons of the past; recognising that we are always stronger, more effective and have more authority when we work with allies across the world and seek to strengthen not weaken multilateral institutions. Standing up for Britain, speaking up for Britain’s values, and building up Britain’s influence in the world, that will be the heart of the foreign policy of any government I lead."

He will outline three examples of how these principles would shape his foreign policy:

- Restoring the UK's commitment to international institutions including the UN, NATO, the Commonwealth and the EU.

"We will rebuild our influence and that starts with the European Union. I want a clear message to be sent to our European partners that an incoming Labour government will be serious about leading once again in Europe and serious also about reforming Europe. Leaving Europe would be profoundly damaging to the lives or our people and the future of our country. We will never put our national interest at risk by threatening to leave."

- Learning lessons from the past, including the 2003 Iraq war, in how Britain uses military intervention

"Today, we face failed states and civil wars across the entire wider Middle East region from the western Sahel through to Somalia and Sudan, from Yemen to Syria and Iraq, and in both Afghanistan and Pakistan….all this matters for the UK. These conflicts are already spilling over into Europe through terrorism, growing illegal migration, organised crime and all these will worsen if the conflicts intensify. So we must respond at home and abroad. We must do all we can to protect our borders, investing in capable intelligence and security services.

"The challenge posed by ISIL’s barbarism is the most pressing case. It was right that the UK joined other nations in air strikes against ISIL targets in Iraq. But military action alone will not defeat ISIL. A long-term multinational political strategy, with regional actors playing a central role, is essential for tackling the rise of extremism across the region and at home. And as we do so we must also learn the lessons of previous interventions. These are the vital lessons of our recent past and I will not forget them. Legitimate interventions must be supported by international, regional and local players, carried out with a clearly defined strategy, as well as include a comprehensive transition and post conflict strategy."

- Putting reducing inequality, tackling climate change and promoting human rights at the core of foreign policy

"When it comes to climate change, we will help set ambitious emissions targets for all countries, reviewed every five years, a goal of net zero global emissions in the second half of this century. None of this will happen by itself. It will take concerted action by countries all across the world and require Britain to play the kind of role that I was privileged to shape at the Copenhagen summit during the last government. The UN summit in Paris later this year will be our chance to demonstrate again how this can work and show what Britain can achieve."

Miliband will cite this week's Mediterranean refugee deaths, the sidelining of Britain during the Ukraine crisis and the endagering of the UK's EU membership as examples of Cameron's failures. On Libya, he will say: "In Libya, Labour supported military action to avoid the slaughter Qaddafi threatened in Benghazi. But since the action, the failure of post conflict planning has become obvious. David Cameron was wrong to assume that Libya’s political culture and institutions could be left to evolve and transform on their own.

"What we have seen in Libya is that when tensions over power and resource began to emerge, they simply reinforced deep seated ideological and ethnic fault lines in the country, meaning the hopes of the revolutionary uprisings quickly began to unravel. The tragedy is that this could have been anticipated. It should have been avoided. And Britain could have played its part in ensuring the international community stood by the people of Libya in practice rather than standing behind the unfounded hopes of potential progress only in principle."

On Ukraine he will ask: "Was there ever a more apt symbol of Britain’s isolation and waning influence than the when the leaders of Germany and France tried to negotiate peace with President Putin and the Prime Minister of the United Kingdom was nowhere to be seen?"

Finally, on the EU, he will say: "This government’s approach to Europe means that even when Britain’s interests are shared by other member states, EU leaders are reluctant to support us because they think we already have one foot out the door…. None of this had to be the case.

"David Cameron has done so not because of any great political principle or ideal. Deep down he doesn’t really believe we would be better off out of Europe. He has done it because he has been pushed there by political forces in his own party and by his fear of other political parties in our country. It is the rise of Conservative Euro-scepticism and UKIP that has led him to this position.

"He has taken us to the edge of European exit because he has been too weak to control his own party and too anxious about the rise of Ukip, a rise he could and should have challenged, but pandered to instead."

In response, we can expect the Conservatives to again cite Miliband's stance during the 2013 Syria crisis as evidence of his unfitness to be prime minister, and to warn that Britain's nuclear deterrent is threatened by the SNP. Tory minister Nick Boles recently tweeted: "Ask yourself this. Who does Vladimir Putin want to see running Britain after 7th May? Answer: the man who abandoned the Syrians to their fate and the woman who wants to scrap our nuclear deterrent."

But Miliband speaks with the confidence of someone who knows that his scepticism towards intervention, in contrast to Blair's adventurism, chimes with that of the public. That he has chosen to make this speech now is also further evidence of his belief that he will soon be the man making these grand choices.