US Secret Service - the United States intelligence agency that protects current and former presidents and vice presidents and their immediate families and protects distinguished foreign visitors; detects and apprehends counterfeiters; suppresses forgery of government securities and documents.
It's  blessings not blessing.. The entire clause is ...to secure the  blessings of liberty to ourselves and our posterity....    The blessings of liberty refers to all of the benefits that are  afforded by having liberty.
Our Father, I decree and declare that thou art in heaven; For we declare that thine is the kingdom, the power and the glory, forever amen. I once prayed a public prayer, after which a fellow believer commended me for the spiritual growth they noticed in my life.