WASHINGTON - Sen. Edward M. Kennedy's wife yesterday sounded off on a hot-button political issue, calling on Roman Catholic clergymen to back off their threats to deny Communion to Catholic politicians supporting abortion rights. ``I am deeply saddened and concerned by the threatened denial of Communion to pro-choice Catholic politicians,'' Victoria Reggie Kennedy wrote in an op-ed piece in yesterday's Washington Post. ``This course of action takes both the church and public discourse in this country to a new and dangerous place, and I urge that it be rejected.'' Victoria Kennedy, who is Catholic, urged church officials to let worshipers...