David in Philistia - politics and religion

Do you have any thoughts on 1 Samuel 27? I am struggling with the relationship between the individual, the State and G-d. And I cannot figure out if David’s behavior was justified or not. My notes don’t say much: "In contrast to David’s previous excursion into Philistia, Achish is now ready to receive him because he has become known as a formidable adversary of Saul. Moreover, to offer sanctuary under the circumstances would obligate David and his men to serve at his call in any military venture....David led Achish to believe that he was raiding outposts of Israelite territory when in actuality he was attacking the Geshurites, Girzites and Amalekites." Was deception the only solution? What does this say about politics in general? Are there any concrete laws that are not broken in times of war or exile? When do we obey the State, especially if we live in the Diaspora? How have views on war changed now in modern Israel? I’ve read a bit on the just war theory, is this applicable in Judaism? When it comes to politics and military service can we serve ’two masters’ when it comes to espionage and intrigue? Just wondering...I know this is a huge array of questions, sorry about that, and thanks for any advice and suggestions!

All King David's actions throughout the Bible are monitored and analyzed by our sages and the commentaries. The Redak (R. David Kimchi) in his commentary to Divrei Haymim I, 22:8) on the verse "You have spilt much blood" explains that because King David had killed those people who may have had among them righteous individuals, he was not worthy of having the Temple built by him. Even so King David was not punished for killing those people because his intentions was to kill the wicked so they do not afflict the Jewish people and to save himself in the land of the Philistines. As far as the ramifications on today from this story, these are issues which are dealt with contemporary leading torah authorities who since the establishment of the State of Israel have been dealing with issues of our renewed sovereignty over the Land of Israel and establishing of a Jewish army after a 2000 year recess. There is much literature on this subject in many journals. Indeed politics must be guided by the Torah as well.