Why didn't Morgoth act when he had the chance?

[The Saucepan Man]

Thanks Eru - that seems to tie things up nicely. [img]smilies/smile.gif[/img]

But, it gives rise to another question! I know that Men were vulnerable to temptation by Morgoth (and, later, Sauron). But was he ever likely to have had dominion over Elves? If not, why did he bother?