He surely had the power to do so, and such action would have settled the question of who had supreme power.
لَا رَيْبَ أَنَّهُ كَانَ فِي مَقْدُورِهِ أَنْ يَفْعَلَ ذلِكَ ،‏ مُبَرْهِنًا بِٱلتَّالِي أَنَّهُ صَاحِبُ قُدْرَةٍ فَائِقَةٍ .‏