The right to kill enemy civilians is accepted in war time (consider the slaughter at Dresden at the end of WW2 and the use of atomic weapons on Japan when it was already suing for peace). R. Shapira may be examining this issue to delineate what is permitted and what is forbidden to Israel according to Jewish law. R. Shapira's conclusions may be wrong, or not, but the Supreme Ct rejected an earlier attempt to suppress the book, the police have now released him and even Haaretz admits the book's preface forbids killing non-Jews, all of which suggest the book is not incitement but an examination of the moral-legal issues involved when faced with difficult questions in war time. By the way, Haaretz didn't bother calling the author for his side of the story, whcih says much.
US rally shows support for ex-Marine held by Iran on spying charges (AP)
from the article: Police release rabbi arrested for inciting to kill non-Jews