The communication process between the political elites and the general public, crucial as it is in a democratie system, is suffering increasingly from an information overlaad. The best way to tackle this problem seems to be the improvement of the communication medium, i.e. ofthe political language. Ideology is the most «rational» political language available: it can carry more information about elite decision-making to a relatively modest cost. This problem-definition suggest a sequence of three critical questions. Do the decisionmakers have a political ideology? If so, is it instrumental in the actual decision-making process? If so, why does this ideological factor rarely reach the general public? The article deals with the two last questions from a format point of view. It can be shown, after the necessary conceptual clarifications and contrary to current opinion, that ideology can hold its own in the private forum of political decision-making and fades away when the elites address the public (not the loyalists) in the public forum. The private forum is dominated by the need for policy output and by the necessity of coalition-formation. The adaptation of ideology to this situation depends on its degree of articulation and on the type of coalition-formation. In general the «salience» aspect of ideology is likelyto suffer less than its «position» aspect. The public forum is dominated by the needs of recruiting support and legitimizing proposals. Generally ideology is too costly a device to be used for these purposes.