WASHINGTON — President Barack Obama’s view of the U.S. role in the Middle East and North Africa is being challenged by deepening crises in the very countries he has seen as models for his approach to the volatile region: Iraq, Syria, Yemen and Libya.

After making good on his pledge to end large-scale American ground wars in the region, Obama has inched the military back into Iraq. The targeted counterterrorism campaigns Obama prefers to ground combat have weakened some extremists, but done little to quell the chaos in which terror groups thrive, or ward off the formation of new factions, like the Islamic State. And Obama’s calls for regional governments and local security forces to take the lead for stabilizing their own countries has often only exposed the weaknesses of those institutions.

The White House acknowledges that the terror threat has spread throughout the region, though officials argue the risk to the U.S. posed by groups like the Islamic State is less than when al-Qaida was at peak strength. Still, U.S. defense and intelligence agencies are deeply concerned about the number of countries buckling under a toxic mix of political chaos and security concerns.