The Republican leader of the Senate yesterday served notice that he had all 50 Republican votes behind President-elect George W. Bush’s choice for Attorney General, John Ashcroft, and warned that Democratic efforts to derail the nomination could poison the effort to set a new cooperative tone on Capitol Hill. At the same time, conservative groups, in a counteroffensive of internet organizations, news conferences and phone banks, vowed to redouble their effort to build grassroots pressure for Ashcroft’s nomination. Several conservative women’s groups planned a news conference in support today. Pat Robertson, president to the Christian Coalition, is to deliver a telephone message on behalf of Ashcroft to half-a-million supporters across the next few days. Bush advisers said the President-elect would fight vigorously for Ashcroft, in contrast to the situation with Linda Chavez, who did not give Bush or his aides an early warning that she had allowed an undocumented immigrant to live with her in the early 1990s.