Conservatives are gaining power in Grapevine, fueled by a once-fringe movement that calls on evangelicals to control the seven key “mountains” of American society — including education. A cellphone company with a Christian nationalist agenda heeds that call and sets its sights on winning school board seats in Grapevine, following an example set a year earlier in the neighboring city of Southlake.CORRECTION (Oct. 4, 2023, 08:40 p.m. ET): A previous version of this episode misstated the amount of money Patriot Mobile Action spent in school board elections in North Texas in spring 2022. It was nearly $500,000, not $600,000.