The most important item in the preamble of the constitution would have to be "establish justice". This means that their will be authorized truth. This will begin to give fairness to the people and bring peace across the nation. This is meant to be a way to bring peace to the innocent and give the guilty their fare punishment.
I chose this, because this leads up to all of the other factors and justice is one of the most powerful things you can have. For example, the preamble says that the people