If he does THAT, then I'll quit.


What a pity! Because at first your reaction is not strong enough, and then too strong. But first things first:


We all know situations in which people (whether of the same rank or not) cross our red lines. And it is important to have red lines (--> non-negotiables) and to stand up for them.


There are more effective ways to stand up for your red lines, and less effective ones:


Variant
EffectResult / Conclusion
Quitting (or walking out of the meeting, or getting loud, etc.)Breaking off or interrupting the relationship
Sometimes ok as an emergency brake. Better than doing things you really don't want to do. But the price is high.
Tit for tatIdentifying and defending the red lines
If it works: Stay in the relationship AND defend the red line.
Say nothing and wait and see if he does THAT.Withholding valuable information from the vis-à-visIf it's so important to me that he doesn't do it, then HE needs to know!


How does Tit for tat work?


1) Co-operate, assume that the other party will do the same.

2) If you see red lines in danger, react with sanctions that are costly but not devastating for the other side. 

3) Then go straight back to (1). 


Effective sanctions sometimes require a little creativity. They are presented in the possible form. Example: "It would be out of the question for me to circumvent this law. If you did and I found out, I would report it to the management."


Sources

Summarised and supplemented, based on: The evolution of cooperation, non-violent communication and hypnosystemic counselling according to Gunther Schmidt.