Callista L. Gingrich Callista L. Gingrich is the U.S. ambassador to the Holy See. By this Author Jun 23, 2020 Catholic sisters remain at the forefront of COVID-19 responseCommentary - Given everything that has happened in the world over the last several months, the third "Women Religious on the Frontlines" symposium could not have come at a more appropriate time. Mar 08, 2019 Women of Courage honoree Sr. Orla Treacy is a beacon of light in South Sudan