The escalation of violence in south Sudan should serve as a wake-up call at this critical point in time. Five years ago this week, the government in Khartoum and rebel leaders in south Sudan ended a long and bloody civil war with the signing of the Comprehensive Peace Agreement. Today, with one year left to go before a referendum on southern independence in 2011, the outlook is grim. Last month, the Khartoum government cracked down on protesters and detained senior members of opposition parties.

If the past is any indication of what to expect in the future, 2010 looks like it will be a difficult year in the long struggle to bring peace to Sudan.

In October, the Obama Administration released its Sudan strategy outlining three U.S. priorities for the country, including:

1. Ending the conflict in Darfur
2. implementing the peace agreement between the north and south and
3. ensuring that Sudan does not provide safe haven to terrorists.

While attention from the U.S. is critical to overcoming many political and legal hurdles, U.S. strategy remains weak on the crucial issue of how best to assist people who are routinely caught up in this conflict.

Imagine returning home after years of forced exile to almost nothing. That's what more than two million people have done as they've returned to their homes in south Sudan. They are struggling to rebuild their lives, but they still need schools, medical care, and a way to earn a living -- the basics anyone would need to start over. Women's programs need support to help communities recover. Yet, tensions are rising and families are increasingly under siege from new attacks.

If the security situation in the south further deteriorates around the referendum, people who have recently returned home, whose resources are already severely over-stretched, risk being displaced again. This will make it even more difficult to deliver assistance to them, but it will also be all the more vital. The situation for the one to two million southerners living in the north, whether through forced displacement or by choice, will also need international attention to ensure that their citizenship rights are fully respected in the event of southern independence.

In 2010, planning for the worst will mean maintaining humanitarian aid levels at least as they are now, and preparing to deliver assistance quickly when it is needed, based on careful planning by the Obama administration and Congress. The UN peacekeeping mission in Sudan, UNMIS, must strengthen and enhance its civilian protection capability and finalize its protection strategy. The government of South Sudan, together with international donors, the UN and NGOs, must simultaneously develop and fund a strategy for people returning home, while preparing for massive population displacements. Neighboring countries must be proactive in putting in place contingency plans of their own for receiving refugees from Sudan.

Some people might believe that planning for war makes it inevitable. This is wrong. While we must still do all we can to prevent a lapse back into conflict, we must not keep our heads in the sand. With all the information at our disposal and one full year still to go before the referendum, we cannot permit a situation in which war returns and the international community is caught unprepared, leaving people to suffer while diplomats, peacekeepers, and humanitarians race to mobilize when it's already too late.

This blog post first appeared on the Huffington Post.