Technically. And honestly in this mess that is all we can use.

It would only be considered a crime after it happened. If blairs organisation helped in the implementation.

Planning is basically writing a well researched book. Of course that is a stretched comparison. But accurate as for as equivalents is concerned.

If you wrote a story based on some meglamainiac American president committing actions seen as war crimes. No matter how accurate the set up or understanding of military preparedness in the real world. Or how involved in talking to that president or staff.

If that meglmaiiac copied your book. You would only be seen as a criminal if you aided in the implementation of your books plot.

Currently the plannings plot has not happened (yet). And we have no idea how involved in implementation blairs group would be. But forming the plan is not a crime in itself.