When the Rev. Barbara Williams-Skinner celebrated her 80th birthday late last year with a party at the headquarters of the National Council of Negro Women near the National Mall in Washington, she asked for no presents. Instead, each attendee — clergy of different faiths, Washington insiders and young people she has mentored — left with a small gift bag containing a Faiths United to Save Democracy pin emblazoned with the words “No One Group, Faith, or Race, Can Do This Alone.”