that Tolkien is cynical about pacifism, or that Tolkien supports Pukel-man's idea that Tom has great power but fails to use it?  You say the letter supports those views, but you haven't cited the support. 

Let me cite the portion of the letter that I believe support my argument that Tom is immune because of his pacifism, i.e. that he is not unfairly taking advantage of those who do the fighting, nor could he use his "power" to fight Sauron if he tried -- because it is his refusal to fight that gives him his power in the first place.

"But if you have, as it were taken 'a vow of poverty', renounced control, and take your delight in things for themselves without reference to yourself, watching, observing, and to some extent knowing, then the question of the rights and wrongs of power and control might become utterly meaningless to you, and the means of power quite valueless."

In addition, at the Council of Elrond Gandalf says that although the Ring has no power over Bombadil, Bombadil has no power over the Ring, and would likely lose it.  To me that means that Bombadil's immunity arises not because of his power or control, but because he has "renounced" power and control.  Thus it makes no sense to ask him to "use" his "power" to hold the Ring or fight Sauron -- he is immune precisely because he does not hold onto anything or fight anyone.  He would lose that immunity as soon as he tried to exert control, if indeed he were capable of exerting control.

Yes, in a certain sense Bombadil relies on others to do his fighting.  But I think more precisely he relies on the Higher Powers to handle matters directly, or through their chosen messengers, of which he is not one.  Gandalf is a chosen messenger of the Higher Powers, but once his job is done he acts much like Bombadil.  Frodo is a chosen servant of the Higher Powers, but once his job is done he acts much like Bombadil.  Of the three chief agents in the War of the Ring, only Aragorn is left with a job still to do, so he, regretfully, cannot join Gandalf or Frodo, but must remain in Middle-earth. 

Tolkien also says in the excerpt I quoted that he would not have left Bombadil in the story if he didn't serve a purpose.  Tolkien said many times that the story came to him as he wrote, and grew in the telling, but he also rewrote the whole tale many times, and pondered every word before retaining it in the story.  Most readers do not ponder every word of the story like Tolkien did, but those who do find that they are worth pondering, and that often Tolkien did have hidden purposes that are only revealed by a close reading.  I think those hidden purposes do make a difference for the first-time reader as well, who may not understand every piece in the whole, but can sense the care with which it was put together.

Of course Frodo learns about faith throughout the book.  But Bombadil is the only person -- at least until Gandalf joins him -- who puts faith to the ultimate test by completely renouncing control.

I have said from the start that Frodo only gradually became a pacifist.  Even when he casts away his weapons, one might question whether Frodo has successfully renounced control, for after all he claims the Ring in the end.  But when he returns to the Shire he has really renounced control -- this is the Shire we are talking about, and yet he does not lift a finger in battle, nor does he harm Saruman despite Saruman's obvious danger to others.  It is not in Mordor, but in the Shire, that Frodo truly embraces pacifism and acts like Bombadil.

“I dislike Allegory - the conscious and intentional allegory - yet any attempt to explain the purport of myth or fairytale must use allegorical language.  (And, of course, the more 'life' a story has the more readily will it be susceptible of allegorical interpretations: while the better a deliberate allegory is made the more nearly will it be acceptable just as a story.)” (From Tolkien Letter # 131.)

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