Turkey’s geography and membership in NATO have long given the country an influential voice in foreign policy, but the assertive policies of President Erdogan have complicated its role.

Brazil has long sought a greater role on the world stage, but political upheaval and other enduring challenges have complicated its efforts.

The federal agency has a broad mandate to protect Americans’ health and an expansive global reach. But the COVID-19 pandemic has been one of its most daunting challenges.