The full story (to my knowledge) was:
-After Diana killed Max (or whoever Rucka wanted to use before editorial made him use Max, because originally he wanted to use an OC) a detective from Washington was going to look into the case and he finds Diana guilty of killing the man (no surprise since she already admitted to it).
-The detective asks Superman to be there for Diana's arrest incase she resisted (I don't think Superman was going to be mind controlled, and would have no part in the story before the detective asked for his assistance).
-Superman would decline at first, because Diana is his friend and he didn't want to play a hand in her arrest and doubted he would be needed anyway, but the detective talked him into it.
-Superman and the detective knock on Diana's front door, too which she exclaims "I'm surprised it took you so long, I'm ready to go with you detective." and is taken to a super-human prison.
-(If memory serves) Superman would then go to Batman because he didn't like the idea of Diana being kept in a prison and would try to talk Batman into helping despite her having killed someone. Batman would reply with that he was already coming up with a plan to free Diana and wants Superman's help.
-The two would successfully break into the prison unaware and try to free Diana, but she would refuse to leave her cell because she has to face whatever consequence the American justice system would charge her with. Superman and Batman reluctantly leave.
-Meanwhile the Amazon's aren't very happy with their ambassador being held poisoner and demand America release her. America refuses and declares war on the Amazons. As they helicopter the President away in Marine One an Amazon suddenly steps onboard (while the helicopter is in the air
) and tells the president, "we have hundreds of invisible planes ready to attack the Whitehouse, the Pentagon and every major military institution in your country if you don't surrender immediately."
-The president surrenders immediately. Making the moment the war started to the moment the president surrendered 5 minutes long.
Things get a little choppy in details after that since Rucka never got that far, but ultimately he said Diana would be found innocent and released.
Edit: Basically what happened after was that Editorial
really liked the idea and wanted to expand upon that. They asked Rucka if he would write the story if they switched out his OC with Max and made a larger event out of it, which he agreed to if the concussion was the same, (with Diana being found innocent). They told him "yes" (which they would later backtrack on) and instead made Diana the odd-man out, which Rucka wasn't happy about, and then they blindsided him by telling him his run was going to end soon so he never had time to write a proper concussion to the neck-snap fallout.