Revisiting Bachurim in the IDF: Is Shevet Levi Patur from Milchemes Mitzvah? Are all Bochurim Shevet Levi?

Does Eretz Yisroel need an army or can it totally rely on Torah protection?
Do we have responsibility to serve – besides the learning protection – like we find previous generations?
The Bochurim who aren’t learning should they go to the army?
Can we have Frum battalions run according to Torah?
What’s are we going to do when the Chareidim are a majority?