I think I can safely say that there are very few works of contemporary academic history that suffer under a deliberate manipulation of facts to conform to a particular worldview, although I can think of one or two. But this doesn't mean one can remove bias from the process of writing history any more than one can expunge one's biases from any endeavor (yeah "hard" sciences, I'm looking at you). As Edward Said has long ago shown us, the circumstances of knowledge production bias the knowledge produced, and that is an entirely unavoidable reality.

Yes, there is a liberal political bias among practicing historians, which is reflective of the general liberal political bias in academia as a whole. But I think this tends to be reflected in the type of questions asked rather than the conclusions reached.

It's also worth noting that I am a premodern historian, and that certain fields, particularly the study of specific areas of 19th and 20th c. history (Holocaust, Russia, Race, etc.) and thus are more troubled by the sorts of manipulations most people would call "bias".