The Chippewa Valley school district in suburban Detroit didn’t retreat in 2017 after voters overwhelmingly defeated its proposal to borrow $90 million for spending pitched as “protecting the community’s investment in our schools.” Instead it rebranded the package as if lives were on the line – as an effort to literally protect students. Last year, voters approved the bond proposal with the campaign tag line “safe schools, strong schools” emphasizing the need for new security funding. School districts around the nation have found that security sells in the year since a troubled student killed 17 people at Marjory Stoneman Douglas...