In a private meeting at her Chappaqua, N.Y., home on Friday, Senator Hillary Rodham Clinton offered to help Ned Lamont in his battle to unseat Senator Joseph I. Lieberman by sponsoring a fund-raiser, campaigning by his side and lending him one of her top political strategists. That strategist, Howard Wolfson, said Mrs. Clinton wanted to throw her considerable political weight behind Mr. Lamont because the national Republican Party “is clearly invested in Ned Lamont’s defeat.” “I think they are going to do what they can to see him defeated,” Mr. Wolfson said, adding that he was particularly concerned with “Bush-Cheney...