OFF TOPIC note: This question is hypothetical, therefore comments and answers disputing its hypothesis are off topic. That is, while the question of "Are there actually any trolls and moles here?" may be interesting, that is a different question.
Suppose for the sake of argument, that some minority of users were mostly here in the capacity of employees, such as those of of the Internet Research Agency of St. Petersburg (IRASP), or perhaps not that group, but one using kindred methods sponsored by other nations, corporations and organizations. Their jobs in part being:
Juggling as many identities using persona management software as seems strategically feasible.
Confusing or degrading communication contrary to their employers' wishes. Methods might include voting pools, time wasting questions and comments, red herring questions, or by skillfully offending and baiting emotionally sensitive partisans into some squabble which leads to their banishment or a question closing.
Promoting, whether directly or indirectly, the current slate of their employers' talking points.
Waging covert propaganda war against any other known trolls, if need be. (Or perhaps just pretend to, during budget reviews.)
This wouldn't be all bad. Sometimes a given employer's talking points would in fact be correct, and those users might naturally then provide good answers, or object to bad ones. Employees of opposed groups might cancel each other out.
But sometimes it would be bad. Misleading answers might be promoted, and good answers demoted. Ordinary users might be contemptuously manipulated. The site as a whole might be overly weighted down and founder.
What sort of policies on Politics.SE would help reduce those harms particular to paid trolls and moles?
Note: Answers should not obsess over mere suspicion or identification of specific individuals or groups. Think of it like pest control via sanitation -- a hospital full of stagnant puddles and dark corners provides a more habitable environment for pathogenic organisms, compared to a clean, well-lit hospital. (But it isn't possible for a hospital staff to find each and every pathogenic individual bacterium under a microscope.)