User blog comment:Legolas halfelf/Silmarillion questions/@comment-204.191.85.34-20171104025012

The chief answer is what is said in the Valaquenta "Manwe is dearest to Illuvatar and understands most clearly his purposes." Also, throught the beginning of the Silmarillion, it seems Manwe most understands the Song and is its primary interpreter. This fits nicely with Manwe's delight being in poetry and music. His leadership is not due to being more powerful, but more understanding what Illuvatar wants. Which is really cool, and goes along quite nicely with Tolkien's idea of power and authority. Hopefully this helps!