The greatest power Trump has is military power.
With it he can defeat all enemies, foreign and domestic.
I think the greatest power President Trump has is the grass roots, Boy Scouts. A lot of people are going to come out of their caves and out from under the rocks where they have been hiding, when they see their champion Trump issue the battle cry.
I would say the greatest power Trump has, is the power of God, as prayer warriors petition Him on his behalf.