Our challenge now is to translate the world’s new-found sense of urgency into action and deliver on the commitments made at last week’s London conference on Yemen.

The need to go on the offensive against al Qa’eda is clear. But even if we could eliminate al Qa’eda in the Arabian Peninsula’s current leadership tomorrow, Yemen’s long-term instability would still risk sowing the seeds of an even greater terrorist comeback down the road.

Consider how Yemen might look in two decades: its population doubled to 50 million, its oil wells depleted and its aquifers run dry. Millions of Yemeni refugees, many illiterate and unskilled, pouring across the Arabian Peninsula and beyond. A Yemeni central government, sapped by multiple civil wars, no longer able to exert power outside a few population centres. And al Qa’eda filling the void, enjoying a large safe haven from which to plan attacks against western interests and innocent Muslims globally.

Fortunately, this scenario is not inevitable. To improve Yemen’s prospects – and the security of its neighbours and America – we need a Yemen policy with an eye towards 2030 as well as 2010.

We must continue to partner with the Yemeni government to aggressively take on the terrorists. We are still learning troubling new details about the full extent of the threat. A recent US Senate foreign relations committee staff investigation reported that several dozen Americans, including as many as 36 ex-convicts, have travelled to Yemen, been radicalised, and possibly even received terrorist training.

President Obama is right to ratchet up American security assistance in return for greater co-operation from Yemen. Even before Christmas, the Yemeni government had begun to take the fight to al Qa’eda. But as long as Yemen faces rebellion in the north and unrest in the south, its government will be tempted to prioritise these challenges over fighting al Qa’eda.

Left unchecked, Yemen’s Houthi war – not primarily a sectarian conflict today – could descend into a dangerous regional proxy war along sectarian lines. We must seek diplomatic solutions to contain the fighting, ensure that humanitarian supplies reach its victims, and eventually address its root causes. In southern Yemen, we should encourage the government to address long-standing grievances before unrest becomes insurgency.

Yet we cannot afford to neglect Yemen’s profound development challenges. While a narrow focus on security issues risks creating a damaging backlash, the international community needs to be clear about what it hopes to accomplish, and what commitment it can sustain. Americans, for one, have no desire to practise nation-building in Yemen, and Yemenis certainly don’t want us to. But they do want better access to schools and health care.

Yemen’s poverty is by now well-known, but its vibrant indigenous civil society is not. As a result, relatively modest international development assistance can have a significant impact, if designed to empower local actors. And over the long run, such efforts will be far more important than counterterrorism measures in undercutting the extremist narrative and improving Yemen’s future. The Obama administration’s new assistance strategy, focused on the drivers of Yemen’s instability, is an important starting point.

But international efforts need better co-ordination. For its neighbours, the stakes in Yemen are high. The assistance efforts of countries such as Saudi Arabia and the United Arab Emirates dwarf all other donors. Gulf states understand Yemen’s intricate tribal politics in ways America and Europe can’t hope to match. That is why a crucial objective of the “Friends of Yemen” group formed at the London conference should be to begin crafting mechanisms that match local resources and knowledge with global technical and development expertise.

However, a return of Gulf jobs could be even more significant than their assistance. For centuries, Yemen has been a source of migrant labour. Hundreds of thousands of Yemenis were expelled from overseas jobs when Yemen foolishly supported Iraq’s 1991 invasion of Kuwait. Most of today’s Yemenis weren’t even born then. Convincing Gulf states to turn the page and allow Yemen’s migrant workforce – rigorously screened – to return could be a vital pressure valve for Yemen’s unemployed youth.

Yemen’s many problems are not the outside world’s to solve – but given the country’s dangerous trajectory, inaction is not an option. Even as we act quickly against those who endanger us today, America and its allies in the region and beyond must make a longer-term commitment to ensure that Yemen does not become even more dangerous tomorrow.

**John Kerry is the senior senator from Massachusetts and the chairman of the US Senate committee on foreign relations