In a departure from the rhythms that have long governed American political life, the Republican Party gathered this week for something it has never attempted before: a convention held not in the shadow of a presidential race, but in the quieter, often underestimated terrain of the midterm cycle. President Trump and Vice President JD Vance addressed the assembled faithful together, a pairing meant to project unity and signal that the party intends to treat the coming elections with the full weight of its organizational ambition. Whether this experiment reshapes how American parties approach off