Buffy Sainte-Marie

Although never quite in the same league as the likes of Bob Dylan, Buffy has written some really powerful protest songs, including Universal Soldier and Soldier Blue , both of which which tackle the mindlessness of the military mentality; the haunting lament My Country 'Tis Of Thy People You're Dying and Now That The Buffalo's Gone, both aimed directly at the conquerors of her people, and Cod' ine, a stark warning of the perils of drug taking.
And, like Dylan, she's capable of writing tender love songs, probably the best known of which is Until It's Time For You To Go, a song strong enough to have received many covers, most notably from Elvis and Barbra Streisand.
The sense sorrow and anger at the fate of America and her native people has never left her, and is still very evident in America My Home from 1976, which I rate as one of her most powerful songs.
Unfortunately ( in my view ) she was involved in the writing of the formulaic tear-jerker Up Where We Belong, a 1982 hit for Joe Cocker & Jennifer Warnes, which, as part of her and Jack Nitzsche's score for the film An Officer And A Gentleman, she received an Acadamy Award Oscar for Best Original Song.