Americans United for Separation of Church and State is a group of people who believe that it is important to keep religion and government separate. This means that the government should not make decisions based on one particular religion or force people to practice a certain religion.
Think about it like playing with toys. Each toy has its own rules and you can play with them however you want. But, the toys should not tell you what to do or which toy to play with.
Similarly, religion should be a choice that people make for themselves, and the government should not tell people what to believe or force them to follow a certain religion.
This is important because it allows everyone to have their own beliefs and not feel like they are being excluded or disrespected because of their religion. It also helps make sure that the government is fair and not biased towards one religion over another.
So, Americans United for Separation of Church and State is trying to make sure that the toys (religion and government) play nicely together without one dominating or taking over the other.