In excerpts of longer interviews on several television networks, the president sought to place responsibility for holding off the threat posed by the Islamic State of Iraq and the Levant (ISIL), which has seized areas in the north of the country, and emphasized that U.S. support would be limited and conditional.
Obama suggested that failure to acknowledge minority concerns coupled with uncertainty in forming a government after elections in April had left Iraq vulnerable.
"Some of the forces that have always possibly pulled Iraq apart are stronger now, (and) those forces that could keep the country united are weaker," he told NBC Nightly News. "It is ultimately going to be up to the Iraqi leadership to try to pull the politics of the country back together again."
Obama is sending up to 300 U.S. military advisers to Iraq and has threatened air strikes as Sunni Islamists have gained control of the north of the country and made a push toward Baghdad. Growing mistrust between Shia and Sunni Muslims has heightened tensions in the country, where the United States fought a war from 2003 to 2011, the president said.
Obama, who is under fire from some Republicans for his decision to pull U.S. troops out of the country when he did, defended his decision.
"Just because something is stable two years ago or four, doesn't mean that it's stable right now," he told NBC.
The president said Iraq's challenge is to assemble a government in which Sunni, Shia and Kurd constituencies feel adequately represented.
"Part of the task now is to see whether Iraqi leaders are prepared to rise above sectarian motivations, come together, compromise," Obama told CNN.
"If they can't, there's not going to be a military solution to this problem. There's no amount of American firepower that's going to be able to hold the country together," he said.
Obama said U.S. advisers will determine whether there is a functioning chain of command in Iraq's military. U.S. assistance in establishing joint operations depends on cooperation among Iraq's ethnic and religious groups, he said.
"The terms on which we send in any advisers would be dependent on us seeing that within the military and with the political structure that there remains a commitment to a unified and inclusive Iraqi government and armed forces," he said.