Which Vala tripped Gollum?

[Calacirya]

Originally Posted by Inziladun

Actually, I used to wonder if Gollum hadn't in fact committed suicide by deliberately stepping close to the brink of the chasm and looking away. I rejected that when I read in HOME that Tolkien had considered that idea and decided against it. Still, maybe Gollum didn't make himself fall, but at the same time didn't care if he did. He could die with the Precious and save Frodo at the same time if it happened. And then Fate was free to finish things...

I believe that this idea is closest to the most probably truth, at least from the perspective of Gollum. He surely had no intentions of dying, but it wasn't a terrible end as long as he had the Ring. The carelessness of his misstep really brings foreshadowed elements together, such as:

As spoken by Eru in The Simarillion:

These too in their time shall find that all that they do redounds at the end only to the glory of my work.

And, arguebly, just as importantly, Gandalf tells to Frodo in The Fellowship of the Ring:

For even the very wise cannot see all ends. I have not much hope that Gollum can be cured before he dies, but there is a chance of it. And he is bound up with the fate of the Ring. My heart tells me that he has some part to play yet, for good or ill, before the end; and when that comes, the pity of Bilbo may rule the fate of many – yours not least.

Just to name a poignant two.