The U.N. is searching for its next leader as António Guterres steps down in December after two terms as secretary general. No front-runner has emerged so far.

Guterres, 77, is stepping down at year’s end. Diplomats seek a secretary general who proactively puts the U.N. at the center of resolving global conflicts and enforces cost-cutting and reform. The topic of who will succeed him is expected to be hotly debated this week behind closed doors during the annual U.N. General Assembly in New York. The conversations “will drive a lot of the candidates’ fortunes and separate contenders from pretenders,” said Daniel Forti, head of U.N. affairs at the International Crisis Group.

The U.N. Security Council selects the secretary general in a monthslong process that begins with informal, nonbinding closed “straw polls.” The 15 members vote for candidates, saying whether they are “encouraged” or “discouraged,” or “no opinion is expressed.” The last straw poll was conducted on Sept. 18, and although results are meant to be confidential, they have leaked. Once the Council agrees on a single nominee, it will pass a resolution and recommend the person to the General Assembly. The nominee needs nine votes in favor and no vetoes by the five permanent members — the United States, France, Britain, Russia and China.

Eight candidates were whittled to seven after Michelle Bachelet dropped out on Friday due to low polling numbers. Bachelet, 75, former two-time president of Chile, had also served as U.N. high commissioner for human rights and executive director of U.N. Women. She had one encouraged vote, 11 discouraged votes and three votes of no opinion. So far, no clear front-runner has emerged, according to diplomats and leaked results of three secret straw polls. Forti said more contenders were likely to join or drop out ahead of the Council’s final recommendation. In previous selections, by this time at least one or two front-runners had emerged, diplomats say. The results have been so inconclusive that, for the first time, Forti said, diplomats and U.N. officials are openly wondering what will happen if the Council does not settle on a candidate.

Guterres, 77, a former prime minister of Portugal who also led the U.N.’s refugee agency, has held the post since 2017 and served two terms. He has indicated he is not interested in remaining in an interim role and plans to be in his native Portugal come the beginning of next year, said his spokesman, Stéphane Dujarric. A successor must be chosen before Dec. 31, after which the person would take the helm on Jan. 1, 2027.

Diplomats and a senior U.N. official said Russia had indicated it would veto one candidate, Rafael Grossi, leader of the U.N.’s atomic watchdog, because it was not pleased with how he had handled the standoff between Russia and Ukraine over the Zaporizhzhia nuclear plant. The United States had also indicated it would block Bachelet over her positions on abortion. It also opposes Carolyn Rodrigues-Birkett, Guyana’s ambassador to the U.N., for c...