If Gloria Steinem is the Martin Luther King Jr. of the women’s movement, then Ruth Bader Ginsburg is its Thurgood Marshall.A shockingly short time ago — the 1970s — when discrimination against women was the law, Ginsburg, a Rutgers law professor, argued six gender-discrimination cases before the U.S. Supreme Court, winning five of them.To drive home the inequities of gender-based statutes, her strategy was …