Slippery slope

Slippery slope, boiling frog, foot-in-the-door technique, and creeping normality are terms for similar phenomena, although not necessarily identical, where small but cumulative negative changes in the end cause a large negative effect, despite each small change in itself is not seen as very negative and therefore not very dangerous to accept.

The concept often implies a deceitful propaganda technique, where one party introduces a small change that is negative for another party, stating or implying that no more changes will occur, despite intending to introduce more changes, once the earlier change(s) have been accepted.

The terms are often used by conservatives to criticize various gradual, "progressive" liberal changes of society.