The central theoretical problem of this article is the question of when it is possible for the use of important political terms, such as 'democracy', to restrain ideological change. Terms are said to have normative and/or descriptive use and to be univocal or ambiguous. These different aspects of their usage make possible a number of ways that the semantics of words can be fixed in language at any given time. The different ways that words can be so fixed are classified. These different ways also influence which rhetorical strategies are available to agents who want to influence the meaning or value of words, as part of a broader ideological struggle. Some such possibilities and strategies are explored with the help of an empirical study of the ideological shift to the right that took place in Sweden during the period 1969-1989. Periods of comprehensive ideological change are distinguished from periods characterized by ideological stability.