honest broker, n.All

An Honest broker (n.) is ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠a partner of one party that has blocked a settlement the rest of the world favors.