BOSTON — The Al Shabaab bombings that ripped through Kampala, Uganda, killing 76 people on July 11, profoundly changed the security situation, not just in Uganda but across the whole continent of Africa.
Before the explosions, the violent chaos of Somalia appeared to be removed from the surrounding states and sealed off from the rest of Africa.
Now, with their deadly suicide attacks, the Somali militant group Al Shabaab has shown it will reach into Africa to blast any government that challenges the Islamic extremism it seeks to entrench inside Somalia.
(Read about the African Union's decision to send more troops to Somalia.)
African countries that support the United Nations-backed transitional government of Sheikh Sharif Sheikh Ahmed, particularly those who provide troops for the African Union peacekeeping force in Mogadishu, are now threatened with suicide bombings like the ones that hit Kampala.
Al Shabaab has sent a deadly message that it will strike any other African country that gets in the way of its extremist agenda. As a result Africa is threatened with escalating tensions that could divide the continent between Muslim and Christian.
Of course, Somalia — which for nearly 20 years has defined the term failed state — has never been fully removed from the rest of Africa. There is considerable cross border economic activity between Somalia and Kenya, including the booming trade in khat, the leaves that Somalis chew as a stimulant.
And Somali refugees have spread across Africa reaching all the way down to Cape Town. So there is no corner of Africa that is beyond the reach of Al Shabaab.
The African Union is faced with a dilemma. Should it stand against Al Shabaab in Somalia? Most African leaders do not trust Al Shabaab, especially because of its ties to Al Qaeda. But many African leaders feel uneasy being allied with the United States and Western Europe, the former colonial powers.
But they are even more queasy to side with Al Shabaab because that group has made clear its ambitions to establish extremist Islamic rule do not stop a the Horn of Africa.
The continent is already faced with growing divisions between its Christian and Muslim populations. Nigeria is on the fault line, as can be seen by the ethnic and religious rioting that takes place regularly in northern Nigeria, and so is Sudan. Many other African countries have similar tensions brewing.
The African Union summit in Kampala this week did not back down in the face of the bombings. Showing more resolve than many had expected, the AU leaders made a firm decision to send more peacekeeping troops to Somalia.
But the deeper solution needed is a diplomatic one that finds common ground between the two sides and that can minimize differences between the continent's two main religions.
Finding an equitable balance between Christians and Muslims in Africa will be a serious challenge for years to come. But, with the rise of Al Shabaab, it is a challenge that African Union leaders must tackle now.