Linda Thomas-Greenfield, a career diplomat, is the presumptive President-elect Joe Biden’s choice to serve as the next U.S. ambassador to the United Nations. Ms. Greenfield has a lengthy record of foreign service experience. Her long in-depth involvement in African affairs will help her in her new job as U.S. ambassador to the UN, where African issues constitute a significant part of the Security Council’s agenda. However, Greenfield will also bring with her a bureaucratic foreign policy establishment mindset.