A false balance, also known as a false equivalence, is the assumption that just because there are multiple viewpoints on an issue, all such viewpoints are equally valid and therefore deserve to be given equal weight. It is an informal logical fallacy and a common form of media bias. False balance can lead to the middle-ground fallacy, which is the assumption that just because there are multiple viewpoints, the truth must necessarily be in the middle. False balance gives the appearance of objectivity while actually achieving the opposite by making one side appear much stronger than it actually is.
False balance is a fallacy because the mere existence of multiple viewpoints on an issue says nothing about the relative merits of those positions. For example, while people have multiple viewpoints on whether the Loch Ness Monster exists, those viewpoints are not equally meritorious, since we have no reason to believe that it exists and strong reasons to believe that it does not.
Liberals rely on false balance because they have no real argument against conservative principles. They find a fringe theory and demand that it be given equal time, omit information on the relative strengths of the viewpoints, or simply manufacture a controversy where none existed before. For example, false balance is a common liberal debate tactic on such matters as homosexuality, evolution, and global warming.