CAIRO — The black flag of jihad flies over much of northern Syria. In the center of the country, pro-government militias and Hezbollah fighters battle those who threaten their communities. In the northeast, the Kurds have effectively carved out an autonomous zone.

After more than two years of conflict, Syria is breaking up. A constellation of armed groups battling to advance their own agendas is effectively creating the outlines of separate armed fiefs. As the war expands in scope and brutality, its biggest casualty appears to be the integrity of the Syrian state.

On Thursday, President Obama met in Washington with the Turkish prime minister, Recep Tayyip Erdogan, and once again pressed the idea of a top-down diplomatic solution. That approach depends on the rebels and the government agreeing to meet at a peace conference that was announced last week by the United States and Russia.

“We’re going to keep increasing the pressure on the Assad regime and working with the Syrian opposition,” Mr. Obama said. “We are going to keep working for a Syria that is free of Assad’s tyranny.”