After months of speculation, the race to become the next UN Secretary-General has reached the point at which support for the official contenders is being tested where it really counts. Two rounds of straw balloting, in which countries are invited to “encourage” or “discourage” the candidacy of each nominee, have already been held by the Security Council. Another is scheduled for next week. Perhaps surprisingly, at a time when the UN is under pressure to appoint its first woman head and recognise the principle of regional rotation by giving priority to candidates from eastern Europe, the apparent frontrunner is neither a woman nor from eastern Europe. He is Antonio Guterres, the former prime minister of Portugal who completed his second term as UN High Commissioner for Refugees last year.

In the first straw ballot on July 21, 12 of the Security Council’s 15 members registered their encouragement for Guterres’ candidacy, with none against. In the second round, two weeks later, 11 maintained their encouragement while two registered discouragement. In most elections, these figures would be enough to make Guterres the runaway favourite, especially since support for his nearest rival fell sharply on the second ballot. But this is not a normal election and there are good reasons for thinking that the job could eventually go to someone else. Straw ballots are a shortlisting device designed to filter out the weakest candidate and should not be confused with the election itself. Special account also must be taken of the Security Council’s five permanent members. It is the interplay between their competing preferences that will ultimately determine the outcome.

China is playing a low-key role having used its diplomatic muscle to insist on an Asian Secretary-General the last time there was a vacancy. France and the UK are unlikely to veto any candidate supported by the others. That leaves Russia and the US, two countries pursuing radically different visions of world order and locked in bitter rivalry over Syria and Ukraine. As during the Cold War, finding someone capable rising above the climate of mutual suspicion between Washington and Moscow is likely to be the UN’s biggest challenge.