Depersonalization
This involves wording issues so that they focus on what one party doesn't like rather than the person who is proposing the unpalatable option. How does this work in practice? Let's go back to our earlier example:
"Well, I can see your arguments for appointing Alison. But I just think James would be better, and you're not going to convince me otherwise."
As a leader, you need to pick this up and rephrase the statement:
"So what you're saying is that while Alison clearly has strengths, James' strengths may well be more important."
From here, you can move the discussion into an objective analysis of the relative importance of different qualities.