In 1984 George Orwell had the ministry of truth rewriting history on a daily basis to suit whatever political policies the governing regime needed to justify. Even though Orwell saw his position in politics as being on the left, that did not stop him looking at both sides of politics as honestly and opened minded as possible. I think he saw that this propensity to rewrite history was not confined to the left, but by far the left were (and still are) the greatest rewriters of history. They do it on a daily basis and seem to have no shame in changing their history to suit the reasons for their latest allegience.
This article covers more than that but does touch on this rewriting of history.