During my studies (conflict resolution), I had the opportunity to ask several mediators and negotiators who had worked on high-profile political cases about lying.
It occurred often, but was by far the least favorite item in the toolbox of a negotiator. Many would rather make emotional / moral appeals to the opposing side than lie.
Not because it wasn't effective (in some cases it could be quite effective), but because the results were very unpredictable. Being called out may undermine the rest of their position... or if they stuck to the lie to avoid this situation they may force themselves into defending a non-ideal positions.
It gets worse! There are now a lot more variables for you to consider, as the hitherto rational party on the other side of the table has been forced to question all of your statements. He is now much more likely to miscalculate true statements and positions as being false. You've now turned your negotiation partner into an (effectively) irrational actor.
It occurred often, but was by far the least favorite item in the toolbox of a negotiator. Many would rather make emotional / moral appeals to the opposing side than lie.
Not because it wasn't effective (in some cases it could be quite effective), but because the results were very unpredictable. Being called out may undermine the rest of their position... or if they stuck to the lie to avoid this situation they may force themselves into defending a non-ideal positions.
It gets worse! There are now a lot more variables for you to consider, as the hitherto rational party on the other side of the table has been forced to question all of your statements. He is now much more likely to miscalculate true statements and positions as being false. You've now turned your negotiation partner into an (effectively) irrational actor.