A prudential judgment is an evaluation of a situation where we use the virtue of prudence in order to determine the best approach to resolving the issue at hand. The Catechism:
Prudence is the virtue that disposes practical reason to discern our true good in every circumstance and to choose the right means of achieving it. . . . With the help of this virtue we apply moral principles to particular cases without error and overcome doubts about the good to achieve and the evil to avoid (1806).
Now, pointing out that sometimes political questions involve prudential judgments doesn’t mean that all judgment is reserved to the individual, so Catholics can do whatever they want. Because prudence is concerned with choosing the good, a prudential judgment does not reflect a merely subjective preference. So we can be held morally accountable for the judgments we make in these matters.
But unlike principles of doctrine and morality, the Church has not definitively taught which specific answers the faithful should embrace when it comes to implementing moral principles—like justice or care for the poor—in the public sphere. And in some cases, differing geographical, cultural, social, or economic circumstances could change which answer is most appropriate for a given community.