Do you embrace a 'just war' theory?

Yes.

A just war is to defend a civil society from barbarians. WWII was a just war in that Hitler had to be stopped to defend humanity. And the Flying Tigers fought a just war defending the Chinese against Japanese depredations.

The Cold War was a just war, and would have been even if it had become hot in the attempt to stop tyrants like the USSR and China from conquering their neighbors by force.

Some wars are less clear-cut, but the motive behind the war is the thing that makes the war just or unjust. Conquering and plundering peaceful neighbors is never just.

Fighting to defend one's country's freedom or that of others is always just. Defending democracies under the American nuclear umbrella is a good example of a just war that has resulted in the longest period of peace between major nations in modern history.

Now that the U.S. is disarming and withdrawing from our world leadership role we will see the state of violence between nations restored to its historical norm, I am afraid.

Today, the war against ISIS barbarity is as just as any war could ever be, but our leadership has lost its backbone as well as its vision, and the world will once again pay the coward's price as a result.

Anyone that goes to war believes they are justified. Only history will determine which side is correct. Of course, it is easy to judge something once it's done.

i don't mean to be concise: I think the crusades was intended to be "just war", However today, when we contemplate going to war, i don't think God enters the picture. Shame on us, as a people. Radical Muslims would like to think, they are fighting for Allah but like others that go to war today, they want to line their pockets and satisfy their physical needs, than to offer up for the GRACE of God.
To answer: yes.