Attendees at Rededicate 250, a Christian-focused prayer rally, on the National Mall in Washington, May 17, 2026. Rededicate 250 promoted the idea that the United States was founded as a Christian nation. (Alex Kent/The New York Times) By JENNIFER SCHUESSLER While the nation’s 250th birthday may have passed, the pitched partisan battles over how to tell the country’s history — in particular the founding story of 1776 — are hardly over. On July 4, hours before President Donald Trump gave an…