Now that we have passed the fifth anniversary of the U.S. invasion of Iraq, it's a good time to step back for a look not at how we went wrong but what we need to do to get on the right path.

It has long been a staple of the anti-war movement that there can be no meaningful peace without justice on a global scale. Those of us living in the First World, especially in the United States, cannot pretend to be working for peace unless we also are working for a more just and equitable distribution of the world's resources.

The anti-war/peace movement, therefore, must also be a movement focused on the grotesque inequalities in a predatory corporate capitalist system. In a world where half the population lives on less than $2 a day, it's clear that the global economy is itself a form of war on billions of people. In such a profoundly unjust world, armed conflict is inevitable because there always will be resistance to inequality. Powerful states will respond militarily to any threat, real or perceived, to their dominance.

In other words: No justice, no peace.

Now it's time for us to take the next step: We must recognize that there can be no justice over the long term without sustainability, and creating a sustainable world will require not only radical change in systems and structures of power but also a radical change in the way we in affluent societies live.

It's time to recognize that if we are serious about the values of equality that we claim are the core of our politics, we must scale back the level at which we live.

No reduction in First World consumption, no justice; and no justice, no peace.

One cannot be a serious peace activist without putting peace in the context of justice and sustainability, and the high-energy/high-tech lifestyle of the First World is not sustainable and not compatible with the demands of justice. Meaningful peace requires real justice, which means we must learn to live with less.

We could start by applying a "Golden Rule" of consumption. Working from the common moral principle that we should follow a path based on rules that we would be willing to apply to all, we could begin with this: Consume at a level that, if applied throughout the world, would allow all people a decent life consistent with long-term sustainability. That doesn't prescribe a destination but suggests a direction; instead of anyone sanctimoniously dictating a specific lifestyle, we can collectively recognize that we must move toward living lower on the food chain, using far less energy, consuming far fewer of the planet's limited resources, generating far less toxic waste.

Though some might see this as a sacrifice - and in some sense, of course, we will have to give up material things that we have come to rely on and enjoy - this moment in history also provides us with a chance to redefine what it means to live a good life. Rather than accept the mad scramble to accumulate goods and insulate ourselves from the natural world - the good life as defined in a consumer capitalist society awash in high-tech toys and mass-mediated entertainment - we can reorient ourselves toward the traditional definition of a good life in terms of community and connection with others, service and sacrifice for others, and a deeper sense of meaning for ourselves.

Eloquent calls for peace are easy to make from the material comfort of the First World. Moving beyond that to a demand for meaningful justice gets us closer to the goal. A commitment to a sustainable level of consumption should be at the core of this work.

It will be a struggle, of course, often confusing and sometimes painful. But we can remember that there is joy in the struggle for a better world, which is always at the same time a struggle to become more fully human.