Primary Schedule

Someone please explain the logic behind having state primaries on separate days – leading to the nominees being chosen before each state has a chance to vote. This makes several states irrelevant in the selection process. Why not have each state’s primary or caucus all on the same day? Give each state the chance to have their voice heard.Instead, we have the current system with primaries and caucuses being spread out over the course of several months, leading to voter-apathy and a lack of interest in some states. I am sure there is some previously thought out political justification for this current approach, but it feels like logic is often lost or overlooked in some “established” methods.