Comment by teiferer

A revision control system is a tool the journalists could use to achieve this. Commits to the 'enacted' branch could have commit messges documenting the context (when, how, why, who). Unmerged branches could represent proposed but ultimately rejected (or still in progress) changes with the same amount of meta data.

Of course a tool itself doesn't solve the problem. You need somebody to use the tool. But the tool makes it easier to solve the problem.