Why didn't Saruman go to the Shire to take the Ring?

[Gordis]

Originally Posted by Legate of Amon Lanc

Well, I think Sauron was a bit naive in his power, I think - he believed that Saruman would not be able to withstand him, that he is a coward (in which he was right), and will hand over the prisoners and not dare to start anything in fear of Sauron's vengeance if he did. It was possibly also that "you send forty Orcs, I send forty Orcs, they will have a nice cooperation", just Saruman proved to be more daring here and sent twice more. (Or maybe it was "Let's meet by the river, each of us will send exactly twenty Orcs." Grishnákh comes with forty: "Guess what. Sauron lied." Uglúk: "Guess what. Saruman lied... more!" )

The idea of a bit naive Sauron doesn't appeal to me at all. If he appears "naive", than there must be something we are not aware of, IMO, something we have overlooked. And I like WCH's explanation a lot: that it was a forced unforeseen cooperation, not a pre-arranged one, otherwise Sauron would have seen to it to "lie more" than Saruman.

Originally Posted by Legate of Amon Lanc

As for the Nazgul, it was some sort of "taboo" - Nazgul simply are NOT crossing the river, that's an order. You have to consider that we are looking at it from our a bit postmodern point of view, but it is something similar as when let's say in some ancient culture, people were banned to wear yellow colour. Sometimes, it did not even have any logical explanation why they should not do so, but it simply was the way it was done. You simply don't do that. Point.

Indeed the nazgul have shown little initiative all through the "Hunt". For instance, Sauron sent them to search the Vales of Anduin, and so they did exactly as told, despite the fact that Khamul assured the WK that it would be pointless, and the WK believed him, but still they didn't turn back.

Yet the nazgul who got his steed killed by Legolas was flying over the West bank of Anduin, breaking the order in letter if not in spirit. And I have got a (perhaps erroneous?) impression that it was the nazgul who had ferried the orcs over the river on his Fell Beast and was supposed to ferry the survivors back:

'If we could cross the Great River, we might,' said another voice. 'But there are not enough of us to venture down to the bridges.'
'I came across,' said the evil voice. 'A winged Nazgûl awaits us northward on the east-bank.'
'Maybe, maybe! Then you'll fly off with our prisoners, and get all the pay and praise in Lugbúrz, and leave us to foot it as best we can through the Horse-country.

That's probably why the Mordor reinforcement numbered but 40 orcs. The tired and irritated Fell Beast must have eaten the forty-first and no one volunteered after that.