Were the Valar Shirking their Duty?

[MasterMothra]

There's a bit of a running theme in good old J.R.R's works, and that is that members of the same race are equals and cannot kill or enslave each other without considerable just cause.

Murder and the eventual destruction and enslavement of Middle Earth is just cause for actions by the Valar.

Melkor was a Vala, of the same initial grace and power as Manwe himself, and thus could not ever be simply be enslaved and never be killed.

He was incarcerated before as mentioned in your post.

Once he destroyed the Two Trees, the Valar were kind of occupied with matters of illumination, and thus were unable to purse Melkor into ME.

I dont quite follow what they were occupied with.

I say again, that if they had just remained in Aman, the Valar could have protected them, and justice would have been done to Morgoth sooner, for the Valar would have been prepared earlier.

The Valar would have protected them just as they did Finwe, the Two Trees and the Silmarils? Melkor would not stop in his quest for domination, ever. This is well documented throughout the text. If the Valar thought otherwise their naivity showed no bounds.