Thomas Jefferson's original draft of the U.S. Declaration of Independence contained the word "inalienable" as defined by John Locke's Second Treatise on Government.  Locke's version of the word was changed in the signed version of the D.O.I. to "unalienable" in order to delineate that it was defined by Thomas Paine's less controversial pamphlets, which used often used the word "unalienable."  Both words referred to properties of mankind that could not be relinquished, but "unalienable" was the preferred usage because it was associated with literature that had a higher acceptance.  Over the years, "inalienable" has become the preferred usage of the term.  It still means rights that cannot be relinquished, even by choice or through coercion.  "Unalienable" has become controversial for one reason: some people can't figure out how it fits with its original definition in the Declaration of Independence.  For that reason, and that reason alone, some dictionaries have changed the meaning of the word "unalienable" to mean something different than "inalienable."  They didn't have to go through all that trouble, because "unalienable" actually does make sense in the D.O.I. in its originally intended usage. 

  The D.O.I. doesn't say that "life" in unalienable.  It says that the "right" to "life" in unalienable.  In other words, while it is possible to kill someone, it is not possible to take away that person's sense of self-preservation.  Taken in its entirety, the D.O.I. is saying that a person will keep fighting, regardless of other considerations, any government that does not recognize his right to live, and his right to pursue happiness in the way that he or she sees fit.  The D.O.I. is a statement about the self-evident nature of man, how government can best work with that nature, and what recourse man has when it doesn't. 

 The D.O.I. is the most important and influential document in the history of my country.  Every citizen of my country takes a whole day of every year to honor its anniversary.  The entire meaning of the document hinges around the definition of the word "unalienable."  The D.O.I. loses its sense of being a logical conclusion to the failure of an exact set of principles if "unalienable" is defined merely as "things that shouldn't be taken away."  I don't care if you call it "unalienable," "inalienable," or "moo-juice cocktail" as long as the meaning still represents what Thomas Jefferson intended: rights that cannot be relinquished or taken by any means.