No need to explain

OBI-WAN: Let her go!

ANAKIN releases his grip on the unconscious PADME and she crumples to the ground.

ANAKIN: You turned her against me.

OBI-WAN: You have done that yourself.

ANAKIN: You will not take her from me.

ANAKIN throws off his cloak.

OBI-WAN: Your anger and your lust for power have already done that.

OBI-WAN flings off his cloak.

OBI-WAN: (continuing) You have allowed this Dark Lord to twist your mind until now . . . until now you have become the very thing you swore to destroy.

They circle each other until OBI-WAN is near PADME. He places his hand on her.

ANAKIN: Don’t lecture me, Obi-Wan. I see through the lies of the Jedi. I do not fear the dark side as you do. I have brought peace, justice, freedom, and security to my new Empire.

OBI-WAN: Your new Empire?

ANAKIN: Don’t make me kill you.

OBI-WAN: Anakin, my allegiance is to the Republic … to democracy.

ANAKIN: If you’re not with me, you’re my enemy.

OBI-WAN: Only a Sith Lord deals in absolutes. I will do what I must.

(ignites his lightsaber)