The assumption that just because one event occurs, it will automatically lead to a series of undesirable events even though there is no relationship between the action and the projected events
in interpretation, if you accept one tainted or false idea, that will lead to accepting other false beliefs One step off the true and narrow and your belief system will begin an "inevitable" slide See Propaganda
A tricky precarious situation, especially one that leads gradually but inexorably to disaster: " a clear boundary to confer personhood on a human being... we approach a slippery slope that ends in the disposal of inconvenient people" (Steven Pinker)