[The Might]

I'm going to now try make a post especially concerning Hobbits' laws as far as the time period before and after the War of the Ring is concerned.

Now as far as the Shiriffs are concerned:

The Shirriffs were the name that the Hobbits gave to their police, or the nearest equivalent that they possessed. They had, of course, no uniforms (such things being quite unknown), only a feather in their caps; and they were in practice rather haywards than policemen, more concerned with the strayings of beasts than of people. There were in all the Shire only twelve of them, three in each Farthing, for Inside Work. A rather larger body varying at need, was employed to 'beat the bounds', and to see that Outsiders of any kind, great or small, did not make themselves a nuisance.

There is no mention of any sort of regularly meeting law-making body in Tolkien's descriptions. The Shire-Moot, he tells us, had ceased to meet, and in any case its meetings were too infrequent at any period to allow for regular legislation. One of Tolkien's letters (Letters, Carpenter, 1981, letter #214) mentions the establishment of a rule regarding succession to the property of Shirefolk who passed over sea, and later refers to a "ruling of Master Samwise" (who was then Mayor)

It thus seems that the Mayor combined both the legislative and the executive power in the Shire, and probably because the Mayors of the Shire all seem to be very good of heart (Sam, Frodo or Will Whitfoot) this system worked very well for the Hobbits.
Tolkien says elsewhere (Tolkien, 1965, p.30) about the Shirefolk's view of law:

Yet the Hobbits still said of wild folk and wicked things (such as trolls) that they had not heard of the king. For they attributed to the king of old all their essential laws; and usually they kept the laws of free will, because they were The Rules (as they said), both ancient and just.

"String, or nothing" shrieked Gollum, which was not quite fair- working in two guesses at once.
"Both wrong" cried Bilbo very much relieved; and he jumped at once to his feet, put his back to the nearest wall, and held out his little sword. He knew, of course, that the riddle- game was sacred and of immense antiquity, and even wicked creatures were afraid to cheat when they played at it. But he felt he could not trust this slimy thing to keep any promise at a pinch. Any excuse would do for him to slide out of it. And after all that last question had not been a genuine riddle according to the ancient laws.

So it seems that in the case of the Hobbits using the ancient, unwritten laws, but that were known to all was working very well until, as Legate very well pointed out, Sharkey and his ruffians came along and destroyed this system by imposing too many rules.


Now, I said I'd post mostly about Hobbits, but I have found some interesting quotes about other people as well - the Elves of Lorien.

'The agreement was made without my consent,' he said. 'I will not walk blindfold, like a beggar or a prisoner. And I am no spy. My folk have never had dealings with any of the servants of the Enemy. Neither have we done harm to the elves. I am no more likely to betray you than Legolas, or any of my other companions.'
"I do not doubt you," said Haldir. "Yet this is our law. I am not the master of the law, and cannot set it aside. I have done much in letting you set foot over Celebrant." Gimli was obstinate…"You cannot go back," said Haldir sternly. "Now you have come thus far, you must be brought before the Lord and the Lady. They shall judge you, to hold you or give you leave, as they will."

We already saw that in the case of Thranduil he possesed the power to decide what would happen to the prisoners, and it seems to be the same in Lorien with Galadriel and Celeborn. Haldir has no right to decide, only the "Lord and the Lady" are the masters of the law. It does sound to me quite like a totalitarian regime...but this doesn't necessarily have to mean a bad thing.
I think that totalitary systems have a bad name especially because of the consequences of dictatorships in communism or fascism. But here in Lorien, the law seems to work very well. The Silvan Elves clearly trusted the far superior knowledge and wisdom of Galadriel and Celeborn and so did not oppose their judgements.

Welcome Gimli, son of Gloin. It is long indeed since we saw one of Durin's folk in Caras Galadhon. But today we have broken our long law. May
it be a sign that though the world is now dakr better days are in hand, and that friendship shall be renewed between our peoples.

And personally when Celeborn says "we" I think he is talking about Galadriel and himself, since they are those with the power of decision in Lorien.

Ok, and lastly, something about diplomacy in ME, and also other unwritten laws. As shown in a quote from "The Black Gate opens":

Aragorn said naught in answer, but he took the other's eye and held it, and for a moment they strove thus; but soon, though Aragorn did not stir nor move hand to weapon, the other quailed and gave back as if menaced with a blow. 'I am a herald and ambassador, and may not be assailed!' he cried.
Where such laws hold it is also the custom for ambassadors to use less insolence. But no one has threatened you. You have naught
to fear from us, until your errand is done.

So customs, and laws of diplomacy also exist in Middle-earth, and are respected here by both sides more or less. This is one reason why I didn't like seeinf Aragorn kill Mouth of Sauron in the films, it made little sense that someone like Aragorn would break these customs.