The power of earthly kings, governors and emperors can be understood rightly from the exchange between Pilate and Our Lord Jesus Christ:
10 Pilate therefore saith to him: Speakest thou not to me? knowest thou not that I have power to crucify thee, and I have power to release thee?
11 Jesus answered: Thou shouldst not have any power against me, unless it were given thee from above. (Gospel according to St. John, chapter 19)
If we can understand how Christ willingly subjected Himself to the injustice of men, we can slowly reflect how we ought to imitate Him in respecting human authority. Obeying and imitating Christ, the early Christians boldly accepted persecutions and martyrdom in the hands of immoral rulers.
Our Lady, as Queen of heaven and earth, really has power but she is humble and simple and desires only the Will of God. God does not desire the death of a sinner and demonstrates this by accepting the cruel death on the Cross to save sinners but on Judgment Day, He will order those who disobey Him to be thrown into everlasting fires. Our Lady will not use her power to condemn us but to plead for us before Her Son and because She has found favor with Him, He will accept Her prayers for us, unworthy sinners. If today we make ourselves a slave of Her who desires only His Will, The King will pity us and give us graces to persevere. On Judgment Day, She who desires only the Will of God, will not at all intervene when He condemns the demons and bad-willed people to hell.