The phrase "battle lines" means the positions taken by opposing forces in a conflict or competition. It represents the places where the two sides are ready to fight or compete against each other. Full definition
Then we drew battle lines down the middle over which the other person wasn't supposed to cross and proceeded to eat until we wanted to pop. (wellnesting.com)
And with those old battle lines of rich vs. poor brought into sharp relief once again, its message feels right on point. (cinema-stache.com)
There are many battle lines when it comes to introducing voice assistants to new users. (voicebot.ai)