[Galadriel55]

I would say that Sauron planted the seed, but the thoughts grew in both of them independently of him and of each other.

With Denethor, the source of that kind of thinking is a basic mistrust of other people. Instead of allies helping each other, you see one using the other, and maybe even misusing him. Denethor's mistrust is directly related to his nightly reality shows (how proper to name it such...). He grew to trust none of Gondor's allies, no strangers, not even all of his own people. And, on top of that, Gandalf did not seem to be a figure that would easily invite his trust - he knows a lot, he does not talk of everything, he brings bad news, etc. It's easy then to go to the next step and say that Gandalf is using Gondor for his own hidden purposes.

With Saruman, it's less of a direct correlation, but you could still trace some of it. He used some tools of his own back in the day, and he still continues to use (and misuse) Wormtongue. Gandalf, Radagast, Lotho, and the White Council are some examples. After so many years of living like that, perhaps he became incapable of imagining that other people make use of each other (ie help each other) with purer motives. Perhaps he perceived Gandalf's good intentions but was twisting the situation around a bit (and, I mean, it's not too much of a twist if you think of it) to hurt the hobbits even more, which is more believable. The difference between Saruman's statement and Denethor's is that the latter applies the term "tool" to himself; Saruman, on the contrary, does not consider himself as one of Gandalf's tools, so his exact emotions and motives are more difficult to pinpoint. Overall, though, I think that by applying the term he did not intend to accuse or malign Gandalf; I think his main goal was to hurt the hobbits and add regret and suspicion/mistrust to bitterness and sorrow. Either way, the reason would be that he turned against the world, and that would be due to Sauron's pursuasion.

Reading that chapter, though, I found that Saruman's lexicon became very similar to Gollum's way of speaking. No precioussses, but several words and phrases here and there, some of the attitude. You even see the last glimmer of Smeagol come through in him when he says "You have grown, Halfling". He's been soaked for so long in Sauron's influence and in his own corruption that he's being Gollum-ised. I forget what point I wanted to make with this observation, but it's really interesting. Saruman is a darn interesting character.

Anyways, I think that you've made a very interesting observation, Zil, and I want to hear what others think of it.