Even though at present Satan temporarily rules over the world, he is but a usurper who has occupied it by force.
When the Lord Jesus died on the Cross He Already Cast Out the prince of this world.
In His death He Despoiled the principalities and the powers … and made a show of them openly, Triumphing over them in it.
Although the world still lies under the evil one, it is totally illegal.
And God has appointed a day when the Kingdom shall be Retaken and His Son shall be King over this world for a thousand years, and onward, then, to eternity.