Damned if you do, kablammed if you don't

[Raynor]

Melkor smiting the children will not deprive Eru of them

I believe your tongue is firmly placed in your cheek . Eru had far greater plans with the Children than to allow this species to be crushed

Originally Posted by Ainulindale, Silmarillion

And they saw with amazement the coming of the Children of Iluvatar, and the habitation that was prepared for them; and they perceived that they themselves in the labour of their music had been busy with the preparation of this dwelling, and yet knew not that it had any purpose beyond its own beauty.
...
[] of their operation everything should be, in form and deed, completed, and the world fulfilled unto the last and smallest.

Some of the reasons of creating the Men is for them to bring their part to Creation, to inherit Arda, and that their deeds should redound to the glory of Eru.

[Elmo]

As is mentionied in this thread, it doesn't seem to be Eru's style to step in and protect men. (to smite them on the other hand... ) If he wouldn't step into his creation and protect men from Sauron why would he protect them from Melkor in this case?

[Raynor]

Originally Posted by hhaim

it doesn't seem to be Eru's style to step in and protect men.

Matters of style can be debated endlessly, however, even if we don't see burning bushes and the likes, the hand of Eru is ever present, esspecially since everything depends on him (cf Silmarillion & Athrabeth).