ASOIAF/GOT: how responsible is Catelyn for the War?

If Bran had listened to Catelyn and had refrained from climbing the tower, Joffrey doesn’t send the assassin after Bran. How responsible is Bran for starting the War?

If Cersei and Jaime don’t commit treason by fucking in an abandoned tower, Bran never sees him and never gets defenestrated. How responsible are Jaime and Cersei for the War?.

If Lysa never kills JOn Arryn, Ned never travels south. How responsible is Lysa for the War?

If Joffrey hadn’t set the assassin after Bran, Littlefinger doesn’t frame Tyrion. How responsible is Joffrey for the War?

If Tywin doesn’t choose to send an army into the Riverlands, slaughtering innocent smallfolk, killing their livestock, burning their homes and fields, then there is no war. How responsible is Tywin for the War?

If Arya doesn’t humiliate Joffrey at the Ruby Ford, maybe Joffrey doesn’t kill Ned(who knows?) How responsible is Arya for the War?

If LIttlefinger doesn’t lie to Catelyn about the dagger, Catelyn at most gives Tyrion her icy shoulder at the Inn. War does not begin.

How responsible is LIttlefinger for the War?

Out of all these people only ONE person was TRYING to create a civil war. And he would have kept trying. He did it by persuading Lysa to kill Jon Arryn. He did it by lying to Catelyn about the dagger.

What would he have tried next? We’ll never know because Catelyn and Tyrion happened to meet in the Inn at the Crossroads.

A chance meeting, as they say in Bree.

Written Sept 9