The first phase, an air campaign with nearly 145 airstrikes in the past month, is already underway to protect ethnic and religious minorities and American diplomatic, intelligence and military personnel, and their facilities, as well as to begin rolling back ISIS gains in northern and western Iraq.

The next phase, which would begin sometime after Iraq forms a more inclusive government, scheduled this week, is expected to involve an intensified effort to train, advise or equip the Iraqi military, Kurdish fighters and possibly members of Sunni tribes.