Riker: Captain, why are we out here chasing comets? Picard: Let's just say that Starfleet has every confidence in the Enterprise and her crew. They're just not sure about her Captain. They believe that a man who was once captured and assimilated by the Borg should not be put in a situation where he would face them again. To do so would introduce an unstable element to a critical situation.
Riker: That's ridiculous. Your experience with the Borg makes you the perfect man to lead this fight.
Picard: Admiral Hayes disagrees.
Riker asks Picard why they are out here chasing comments. Picard responds that it is not the fleet they lack confidence in, but him as the Captain due to his prior assimilation with the Borg and therefore do not want him to face them again. And that they would consider him an unstable element. Riker disagrees citing that his experience should make him the perfect leader but Picard explains that Admiral Hayes disagrees.