Rep. Heath Shuler (D-N.C.), a staunch member of the Blue Dog Coalition, said on Sunday that if Speaker Nancy Pelosi does not step aside this week in her quest for minority leader in the new Congress, he would challenge her for the post.Shuler called Pelosi's candidacy "unacceptable" and urged his his party to move in a more moderate direction after a bruising losses in the midterm election.