Does the Catholic Church require a valid marriage license before they will marry someone? In other words, can I be sacramentally married in the church without being legally married in my state?
It’s required in the U.S. I’m not sure about other countries.
May I ask why?
No, not under normal circumstances. It would require permission of the bishop:
Can.* 1071 §1. Except in a case of necessity, a person is not to assist without the permission of the local ordinary at:
2/ a marriage which cannot be recognized or celebrated according to the norm of civil law;
Can.* 1130 For a grave and urgent cause, the local ordinary can permit a marriage to be celebrated secretly.
Can.* 1131 Permission to celebrate a marriage secretly entails the following:
1/ the investigations which must be conducted before the marriage are done secretly;
2/ the local ordinary, the one assisting, the witnesses, and the spouses observe secrecy about the marriage celebrated.
Can.* 1132 The obligation of observing the secrecy mentioned in ⇒ can. 1131, n. 2 ceases on the part of the local ordinary if grave scandal or grave harm to the holiness of marriage is imminent due to the observance of the secret; this is to be made known to the parties before the celebration of the marriage.
Can.* 1133 A marriage celebrated secretly is to be noted only in a special register to be kept in the secret archive of the curia.
Because marriage has a public dimension.