How citizenship is understood depends on the person making the determination. The relation of citizenship has never been fixed or static, but constantly changes within each society. While citizenship has varied considerably throughout history, and within societies over time, there are some common elements but they vary considerably as well. As a bond, citizenship extends beyond basic kinship ties to unite people of different genetic backgrounds. It usually signifies membership in a political body. It is often based on, or was a result of, some form of military service or expectation of future service. It usually involves some form of political participation, but this can vary from token acts to active service in government.