All of these metaphors suggest that allowing one practice or policy could lead us to allow a series of other practices or policies." Bruce Waller says it is lawyers who often call it the "parade of horribles" argument while politicians seem to favor "the camel's nose is in the tent". Given the disagreement over what constitutes a genuine slippery slope argument, it is to be expected that there are differences in the way they are defined. Lode says that "although all SSAs share certain features, they are a family of related arguments rather than a class of arguments whose members all share the same form." Various writers have attempted to produce a general taxonomy of these different kinds of slippery slope. Other writers have given a general definition that will encompass the diversity of slippery slope arguments. Eugene Volokh says, "I think the most useful definition of a slippery slope is one that covers all situations where decision A, which you might find appealing, ends up materially increasing the probability that others will bring about decision B, which you oppose." Those who hold that slippery slopes are causal generally give a simple definition, provide some appropriate examples and perhaps add some discussion as to the difficulty of determining whether the argument is reasonable or fallacious. Most of the more detailed analysis of slippery slopes has been done by those who hold that genuine slippery slopes are of the decisional kind. Lode, having claimed that SSAs are not a single class of arguments whose members all share the same form, nevertheless goes on to suggest the following common features. Rizzo and Whitman identify slightly different features. They say, "Although there is no paradigm case of the slippery slope argument, there are characteristic features of all such arguments. The key components of slippery slope arguments are three: Walton notes that these three features will be common to all slippery slopes but objects that there needs to be more clarity on the nature of the 'mechanism' and a way of distinguishing between slippery slope arguments and arguments from negative consequences. Corner et al. say that a slippery slope has "four distinct components:  The alleged danger lurking on the slippery slope is the fear that a presently unacceptable proposal (C) will (by any number of psychological processes—see, e.g., ) in the future be re-evaluated as acceptable." Walton adds the requirement that there must be a loss of control. He says, there are four basic components, "One is a first step, an action or policy being considered. A second is a sequence in which this action leads to other actions.