Without having read the book I can only speculate, but within the context of critical theory I would expect this to refer to what lay people call 'spin'. Political thought used to be driven by significant events: e.g. (in no particular order, and from an unfortunately American perspective), the assassination of Prince Ferdinand, the Japanese bombing of Pearl Harbor, the Watergate break-in, the Reichstag bombing, the Boston Tea Party, the Battle of Waterloo, 9/11, etc, etc. These events served to galvanize public opinion and unify disparate groups of people around some particular course of action. In part, this is merely politics leveraging human nature; we tend to think in terms of narratives driven by significant events, and so significant events were used to guide people into politically necessary (or at least politically expedient) narratives.
However, the competing information monopolies of the modern era have turned this principle inside-out. Politics is no longer driven by significant events; politics tries to drive events into (in)significance. Events that actually occur are attached to multiple narratives aimed at particular political outcomes, without much concern over whether the narratives are consistent with each other or with the 'facts' of the event. This includes the meta-narrative of merely ignoring or distracting from a significant event in order to keep it from being politically motivating. And then there are the events that do not actually occur — nonsense such as the Q-cabal conspiracy crap, the 'yellow cake' lie from the W Bush administration, the recent GOP disinformation meant to cast Ketanji Brown Jackson as pro-pedophile — that are manufactured specifically to generate a political moment that political actors can use.
In other words, where politics used to latch on to significant historical events in order to drive political thought, it now latches on to the capacity to create confusion and counter-narratives in order to fortify political goals against the occurrence of significant events. The universe of information tends to collapse under the pressure.
But again, this is my assessment of the axiom from my experience with Critical Theory, not an analysis of Povinelli's (or anyone else's) work. Take as intended...