Sometimes, especially in political discourse, a statement will include language intended to establish the speaker’s membership in a particular tribe, to establish that they share goals and values with their audience, and indicate that any mistake or criticism is made in good faith.
This kind of preamble is the ‘shibboleth’ of a statement: a proof of membership, intended to be in a form that only a true member of the tribe could offer.
The presence of a shibboleth reveals more than just group membership. It also indicates the audience to whom the person is speaking (it’s less necessary when ‘preaching to the choir’); the goodwill with which they are speaking (it builds connection and common ground); the desirability of being seen as part of a group, and the precariousness of group membership (it’s more common if the speaker is concerned about the possibility of being expelled by the group, e.g. when criticizing the group); the power of the group (it’s more common for more powerful groups); and the tactics of the group (it’s more common for groups that punish the outgroup).
Thus shibboleths are common on the Progressive Left, not least because by its nature the Progressive Left pushes the envelope on policy, often adopting experimental policies as common causes (for example, consider the slogan, “Defund the police”, a policy quite far from the mainstream and relatively untested). As a result, some members of the Progressive Left might question those policies, and wish to push back, or even just think through, the proposed policies. But membership in the Progressive Left is relatively precarious: it is a cultural group built on reputations (which are much easier to destroy than create), and it is effectively a youth movement (so many of its wisest members are at risk of ‘aging out’ and being discarded by the incoming cohort). The group has also been politically powerful and willing to wield the power to punish enemies, in particular ‘apostates’ (e.g. academics), who are broadly on the Left but disagree with the full Progressive package.
More recently, though, shibboleths have become common on the Reactionary Right, due to the growing power of that movement. As it has grown in influence and captured more social institutions, keeping on good terms with the broader coalition has become more desirable. Their power is also more explicit than that of the Progressive Left, who wield cultural influence but only indirectly control wealth and the power of the state. Combined with the avowed vindictiveness of the Reactionary Right, the use of explicit power makes shibboleths both appealing and extremely effective – where reputations take a long time to build, groveling before a single powerful decision-maker can be immediately effective.
Note, though, how this changes the form and meaning of the shibboleth. To remain effective, it needs to be more dramatic, delivered more quickly and at higher cost to the speaker. It will often not be directed at the audience, most of whom wield neither explicit nor cultural power, but at a powerful third party (the “audience of one”).
Note also how this change is shaped by changing modes of communication. A longer, more nuanced shibboleth fits a world where longer-form speaking and writing are the norm, particularly among the elite. That encourages shibboleth both by content and form: endorsing the right values while displaying deep understanding of the issues. This is further favored by speaking in writing intended for an exclusive audience.
By contrast, short, public statements as popularized by social media will favor the more extreme and less nuanced form, and will tend towards statements whose mechanism of displaying group membership is the mere willingness to be associated with them.
Interestingly then, the mechanism of displaying group membership may influence the politics of the group: a political group whose members prove themselves by deep and nuanced understandings will favor deep and nuanced policies that are harder to understand and analyze; a political group whose members prove themselves with brief, extreme, and somewhat distasteful statements will favor shallow, radical, and repugnant policies, easier to understand but which many people will be reluctant to endorse.