From James Banner's Being a Historian, p. 164
"Being concerned with the past, works of history can only imply, they cannot as history propose, courses of action; they can evaluate, sometimes magisterially, the conditions of society and culture, but they cannot as history directly help society out of its predicaments. The historians of greatest weight and influence tell stories of times gone by rather than analyze current affairs. They charge the present with meaning by locating it in the past; they do not, and cannot, convey us into the future, Historians may become well known and influential; their works may enjoy brisk and enduring sales; people may seek their advice. But their work must stand or fall, not on the temperament or ideology their authors bring to it, not on their works' arguments for change, but instead on their foundations in knowledge and the power of their presentation. Reform may arise from historical knowledge, but bringing about reform is the province of others--or at least of historians on their days off."