Q 1:
Can any Ummah (nation), however powerful, destroy another if Allah does not will it?
A:
No Ummah, however powerful, can destroy another, except if Allah wills it. Indeed, nothing occurs in the universe without His Permission and Will. (Part No. 3; Page No. 183) Allah says in the Qur'an:
But you cannot will, unless Allâh wills. Verily, Allâh is Ever All-Knowing, All-Wise.
Allah (Exalted be He) also says:
And you cannot will unless (it be) that Allâh wills - the Lord of the ‘Alamîn (mankind, jinn and all that exists).