The "just" war vs. "jihad"

     There are certain conditions that justifies Christians to take up arms. WWII is a clear struggle with evil.   

     But Christians do not engage in "jihad" with non-believers ( - not in my lifetime at least).

     On the contrary, I've heard a rumor that during the ethnic cleansing at Kosovo, the late Pope John Paul II sent armaments to help the Moslems - not the "Christians".