Rarely is the juxtaposition between joy and tragedy as stark as it is in the new nation of South Sudan and the changed nation of Sudan.

I had the honor to participate in the U.S. presidential delegation witnessing independence day ceremonies in Juba, South Sudan.  Along with Ambassador Susan Rice, General Colin Powell, Congressman Donald Payne, Special Envoy Princeton Lyman, and others, I rejoiced as President Salva Kiir took the oath as president of South Sudan last Saturday.  The independence of South Sudan, the world’s 195th nation, is a stern rebuke to the cynics of the world – the cause, one might say, of Juba-lation.  After decades of civil war resulting in more than 2 million deaths, the people of South Sudan now have the chance to chart their own destiny.  And we must be by their side during this journey.

As leader after leader – from UN Secretary General Ban Ki-moon to African Presidents Jacob Zuma (South Africa), Meles Zenawi (Ethiopia), Goodluck Jonathan (Nigeria), and Yoweri  Museveni (Uganda) – stepped to the podium in Juba last Saturday to address 100,000 cheering celebrants, they welcomed South Sudan into the community of nations.  Most significantly, so did President Omar al-Bashir of Sudan with a remarkably conciliatory speech.  For his part, President Kiir called for peace with Sudan, transparent governance, health and education services so desperately needed in the South, and respect for human rights and human dignity.

This was our celebration, too, reflecting the commitment of successive American administrations to resolving this crisis.  Building on the outstanding work of Ambassador John Danforth and others to negotiate the Comprehensive Peace Agreement in 2005, the U.S. Government has been the lead donor of humanitarian and development assistance needed to help the people and government of South Sudan turn the concept of independence into the still-to-be-achieved reality of a functioning government and a stable nation.

Under the direction of President Obama, Secretary Clinton, and Administrator Shah, USAID and its sister agencies have helped provide a million South Sudanese with access to clean water, increased primary school enrolment from one in five to more than 68 percent, provided assistance needed to carry out the January 2011 referendum that led to independence, and built roads, bridges, power stations, and health clinics.

Looking ahead, we are adopting a four-pronged strategy in concert with other bilateral and multilateral partners to strengthen South Sudan’s promising agriculture sector, create the environment needed for private trade and investment, build the human capacity needed to govern the new nation and provide essential services to citizens, and create an international mechanism to multiply the efforts of South Sudan global friends.

We look forward to co-hosting with the new Government of South Sudan an international engagement conference in Washington in late September that will allow the new government to present its vision for the future of South Sudan and engage with partners—governments, international organizations, and the private sector.

But South Sudan’s success also depends on peaceful relations with its new northern neighbor and on the stability of that country.  There, despite Bashir’s generous words on Saturday, the situation remains perilous.  It is critical that the Government of Sudan demonstrate its commitment to governing peacefully within its borders and allow full humanitarian access to assist those in need in Southern Kordofan, Abyei, and Darfur. The Sudan Government and the Sudanese People’s Liberation Army (North) must agree to an immediate cessation of hostilities in South Kordofan.

Further, Khartoum and Juba must come together to rapidly resolve the remaining tough issues left over from the Comprehensive Peace Agreement, including distribution of oil revenues, citizenship determinations, full demarcation of the border, and resolution of the disputed region of Abyei in a spirit of cooperation.

The poetry emanating from the podium in Juba must now translate into the prose of building stable, democratic, and prosperous states in Sudan and South Sudan.  It’s our fight, too.

Before I left the region, I also visited camps of Somali refugees in Ethiopia and food distribution centers in Djibouti to help facilitate the global response to a severe drought and food crisis that threatens more than 10 million people in Ethiopia, Kenya, Somalia, Uganda, and Djibouti.