Certainty relies on flexibility and flexibility relies on certainty. Certainty is about resilience, dependencies and how much variation in one thing creates change in another thing.
Flexibility is about handling change, managing risks and knowing how much control you have over things.
Voters need politicians to be certain, to ensure good decision-making, but not flexible in their moral character.
Voters need politicians to be flexible to cope with external change, but remain uncertain that they (politicians) are always right.
Politicians need voters to be flexible (forgiving of their poor judgements) and certain on Polling Day (certain enough to cast a vote and certain enough to vote for them), but not certain during the rest of their political term, or they’d be out of a (decision-making) job.