Not that they are a modern invention. The sidra describes a delegation of messengers sent from Kadesh to the king of Edom to seek permission for the Israelites to go through his territory (Num. 20:14). The delegation did not succeed, but it is still instructive to study the arguments they put forward.
“Thus says your brother Israel”, the argument began; “You know all the travail that has come upon us, how our ancestors went down into Egypt, and we dwelt in Egypt a long time; the Egyptians dealt badly with us and our ancestors, but when we cried to the Lord He heard our voice and sent an angel and brought us forth out of Egypt…
“Let us pass please through your land; we will not pass through fields or vineyards nor drink the water of the wells; we will keep to the king’s highway and will not turn aside to the right or the left until we have crossed your border” (Num. 20:14-21).
Note which points were made:
1. We and you share a commonality of interest (we are “your brother Israel”).
2. We have a problem (“You know all the travail that has come upon us”).
3. We are not without influence (“The Lord heard our voice and sent an angel”).
4. We have a favour to ask (“Let us pass through your land”).
5. It will not cost you anything (“We will not pass through fields or vineyards…”).
6. We will be out of your way very quickly (“…until we have crossed your border”).
7. Helping us will bring you moral benefit (God will notice).
The ethic of modern diplomacy is more complex but in its own way the Israelite delegation may well have been pioneers in the field of diplomatic process.