As the ebullient husband-and-wife singing team who head the Nashville, Tennessee-based band The War and Treaty, Michael Trotter Jr. and Tanya Trotter are happy to discuss the joy their wonderfully soulful music brings them and their audience. But the couple is also acutely aware of how music can capture and convey life-and-death moments, including the one in 2017, when a deeply despondent Michael was contemplating suicide. Tanya’s pleas and declaration of her abiding love brought him back from the abyss — followed by immediate assistance from the police in Albion, the Michigan town where the T…