The two Republicans seeking to unseat Senator Hillary Rodham Clinton clashed ferociously last night in a debate that centered far more on questions of marital infidelity, nepotism and other personal attacks than on what either candidate would do if elected. Kathleen Troia McFarland, a former official in the Reagan-era Pentagon, repeatedly hammered John Spencer, a former mayor of Yonkers, for having an extramarital affair with a city employee while he was mayor, having relatives on the city payroll, and raising property taxes. Mr. Spencer fought back, accusing her of distorting his record with “lies and innuendos and half-truths” while ignoring...