Marriage IS a sacrament, but it is also a civil status. The state has laws that pertain to married couples, which includes rights, taxes, family, inheritance, etc, etc. So the license is a statement by the state that a couple may enter this civil status and be subjects to the provisions of these laws.
Now if a Catholic couple, having obtained the license, marry before a justice of the peace, ship captain, etc, but not the Church and her ministers, they DO change their civil status, and are LEGALLY married, and are entitled to the benefits provided by law.
Of course, what they are in the eyes of God is an entirely different story. They may be LEGALLY married, but most definitely not SACRAMENTALLY, and therefore have no right to engage in the coventantal mariital embrace.
Now if a Catholic couple, having obtained the license, marry before a justice of the peace, ship captain, etc, but not the Church and her ministers, they DO change their civil status, and are LEGALLY married, and are entitled to the benefits provided by law.
Of course, what they are in the eyes of God is an entirely different story. They may be LEGALLY married, but most definitely not SACRAMENTALLY, and therefore have no right to engage in the coventantal mariital embrace.