Jennifer Steinhauer writes for The New York Times: “In the 90 years since Rebecca Felton of Georgia became the first woman in the United States Senate — sworn in for a mere 24 hours — women remain an anomaly in the upper chamber. But with 20 female senators now in office, an all-time high, women have morphed from the curiosity they were for much of the 20th century into an important new force on key committees and legislation.”