Russia is advocating the importance of a candidate from the Eastern European region, as this would be in accordance with the informal consideration that the job should be rotated between the different regional blocs of the UN.
The talk is also that a woman should lead the organisation. To date, eight men have held this post. Three of these men have come from what is known as the Western European and Others Group, which includes New Zealand and Portugal. Two have come from the Asia Pacific Group, two from the African Group and one from the Latin American and Caribbean Group.
The reason that candidates from the Eastern European group have never produced a Secretary-General is that traditionally they were assumed to be too close to the Soviet Union. In the post-Cold War world, many of these countries are now members of Nato and, accordingly, are now seen by Russia as being too close to the United States.
Slovenia's Turk, who is also a part-time professor who teaches human rights in New York, will have to try to straddle this problem, as does Bokova, the Bulgarian head of Unesco. The difference with Bokova is that she was educated in Moscow and has a very positive relationship with Russia.
Bokova, currently the front-running female candidate, probably got her "discourage" votes from the United States who are angry with her over the process by which Palestine joined Unesco, and the UK, who accuse Bokova of nepotism.
Conversely, Serbia is not a member of Nato, and has excellent relations with Russia, although what the Russians think of the Harvard-educated, very European-looking Jeremic, is unknown.
The hope of both Clark and Guterres is that the politics surrounding all of the Eastern European candidates will cancel all of them out. If that occurs, it could turn into a two-horse race with Clark, the two-time administrator of the United Nations Development Programme, going head to head against Guterres, who was the United Nations High Commissioner for Refugees from 2005 to 2015.
Guterres' handling of one of the most critical issues facing the world has him highly regarded by many, as does Clark's, for her work at the UNDP.
If this ends up in a two-horse race, the big question for Clark is how she fits with the permanent members of the Security Council. Her relationship with Britain is strong, and good with France and China. She had a difficult relationship with the US over the nuclear issue, although she did support America by providing combat troops into Afghanistan in 2001 and non-combat troops into Iraq in 2003.
With Russia, she has avoided getting drawn into the debate over their intervention into the Ukraine, while for Syria, she has been at the forefront of directing the resources of the UNDP to helping the refugees outside of the conflict zone and providing aid to civilians inside of it. Thus, in terms of pure excellence, she should be neck and neck with Guterres. If she gains an edge, it will be because she could end up being the last woman standing.