 President Biden found himself increasingly isolated on Thursday as a small group of his longtime aides and advisors have become convinced he will have to make what they see as the painful but inevitable decision to abandon his campaign for reelection, according to three people who have been briefed on the matter. In recent days, the group has been trying to come up with ways to persuade Biden to step aside from the campaign. Those discussions were recounted by three people familiar with them who, like others in this article, spoke on condition of anonymity to discuss a sensitive situation. There's no indication that any of the discussions have reached Biden himself, according to one of the informed people.