The Bible calls him the mighty one in battle. He has led Israel into wars and conquered for Israel. He is not changed. God is a God of war. Now back to the question, I think the prophets have a job to do here. Israel should still have prophets. So the prophets should go to God to get answers. If it is God's will to stage a pre-emtive strike, the message will be loud and clear to the prophets and if it is his will for Israel not to start a war, then that is his perfect will. Just follow his directives. Whatever his will is, is the right thing to do. Dont forget his promise in Jeremiah 15 v 20. Israel is yet to lose a war.
Russia claims to have hit three ISIS targets in Homs, Syria; 6 other sites also hit (Reuters)
from the article: Would God want Israel to attack Iran?