Sadavir Errinwright is the UN Undersecretary of Executive Administration in the office of Secretary-General Esteban Sorrento-Gillis. Put in other terms, he is the second highest ranking member of The United Nations. Unlike the Secretary-General, Errinwright is much more straightforward with his goals to make sure that the United Nations remains the dominant superpower in the Sol system. He is unafraid to take direct and first action against the The Martian Congressional Republic and it is only the cool and calculating head of his Deputy Chrisjen Avasarala keeping him from escalating things.
 
Errinwright, however much of an Earthist he might be, is not an idiot. He did not get to where he is today by making brash and headstrong actions, and he should not be underestimated simply because of his aggressive tendencies. He is intelligent and willing to do anything to protect Earth, at any cost.