. WASHINGTON — Ngozi Okonjo-Iweala, a Nigerian economist and former finance minister, is poised to become the first woman and first African to lead the World Trade Organization, when the members of the global trade body meet Monday to consider her candidacy for director-general. The appointment would remove a key obstacle to the functioning of the WTO, which has been leaderless during a time of growing protectionism and global economic upheaval brought about by the pandemic. But even with Okonjo-Iweala at the helm and the renewed support of the Biden administration, the WTO, which was founded in 1995 to ensure that trade flows as smoothly and freely as possible, will face steep challenges surrounding its effectiveness as the world’s trade arbiter.