The two pillars of today's Judaism, R.Yosef Karo and R.Yitzhak Luria, wrote entire treatises on gilgulim.
At his hesped for R.Kahane, former Sefardi Chief Rabbi Mordechai Eliyahu said that "R.Kahane was a gilgul of a warrior from the Tenach who knew no fear".
According to Chaim, R.Yosef was already "completely demented, senile and insane" back in 2001, but if the Jewish soldiers aren't up to scratch, then it does say that Hashem's special Providence will not be with them: "You abandon and disgrace us, and do not go forth with our armies" (Tehillim 44).