WASHINGTON (AP) — After rallying dozens of nations to join the fight against Islamic State militants, President Barack Obama is back in the coalition-building business — this time to fight the Ebola outbreak in West Africa. Obama is sending up to 4,000 troops to West Africa to supply medical, logistical and training support to the region's overwhelmed health care systems. A few days earlier, he closed a meeting with visiting defense chiefs on the Islamic State by addressing the need for unity in tackling Ebola. An administration official declined to name other countries on the list, but said specific "asks" for each of them exist, based on their available resources, whether it be requests to build additional treatment centers, provide health care workers or send supplies and-or money. Janine Davidson, a senior fellow for defense policy at the Council on Foreign Relations, said one of the strengths of American leadership is getting countries to contribute at whatever level they can and that Obama's approach is important because stopping Ebola from spreading must be a global and not a regional effort.