Of

[Allen165]

"The most prominent of these essential principles are the doctrines of supremacy and of direct effect, and the preliminary reference procedure."

Is there a reason why the author repeated "of"? It doesn't seem necessary to me.

Thanks!

[bwkcaj_ca]

Yes there is. While perhaps not essential for a clear understanding, given
the the word doctrine has been pluralized, the second "of" makes
it apparent to the reader that there are two doctrines under discussion.

[Allen165]

Yes there is. While perhaps not essential for a clear understanding, given
the the word doctrine has been pluralized, the second "of" makes
it apparent to the reader that there are two doctrines under discussion.

I just don't see how one could misunderstand the sentence if the second "of" were omitted.