If I’d come to Hawaii to sample something of Barack’s past, we were now sitting at the edge of a giant ocean, trying on a version of the future, discussing what kind of house we’d want to live in someday, what kind of parents we wanted to be. It felt speculative and a little daring to talk like this, but it was also reassuring, because it seemed as if maybe we’d never stop, that maybe this conversation between us could go on for life.