Teresa Kerry, the wife of the presidential candidate, has proved herself a key electoral asset ahead of the Democratic convention later this month, writes Nicholas Wapshott Teresa Kerry is perched on a child's chair in the Fort George Community Enrichment Centre in Washington Heights, New York, with her knees uncomfortably close to her chest. Around her in a circle sit a dozen three and four-year-olds, mostly of Puerto Rican-born parents, reading in a Spanish sing-song the nursery rhyme Incey-Wincey Spider. Maria Teresa Thierstein Simoes-Ferreira Heinz Kerry is a shy woman who has been hurled into the limelight somewhat against her...