With months to go before the midterm elections, the shadow campaign for the 2024 Republican nomination is well underway, with at least 15 potential candidates traveling the country, drawing up plans, huddling with donors or testing out messages at various levels of preparation. The quadrennial circus — described by more than 20 people with direct knowledge who spoke on the condition of anonymity to discuss private machinations — has kicked into gear despite the public hints from Trump that he too plans to join the scrum “a third time.”