Annulments unfortunately have become more and more well-known in Catholic circles, and they are still not well understood. Many people think that annulments are basically a Catholic term for divorce, but this could not be farther from the truth. A divorce is intended to dissolve an existing marriage. However, in accordance with God's teaching, the Catholic Church believes that marriages are indissoluble, and that once married, it lasts until one spouse dies. An annulment is a declaration that the marriage never existed, although it appeared that it did.
For a marriage to be valid in the eyes of the Church, there are five conditions. Firstly, the spouses must be free to marry. Secondly, they must freely give their consent to the marriage. Thirdly, they must intend to be faithful to one another, to be married for their lifetime and to be open to children. Fourthly, they intend good for each other. Fifthly, the consent must be given in the presence of two witnesses and an ordained Catholic minister. If one of these conditions is not present at the time of the marriage, then the marriage was never valid and the two persons were not truly married.
The job of a marriage tribunal is to examine witnesses and the couple to determine whether these five conditions were present at the time of the marriage so that it was indeed a valid marriage. If the tribunal finds that these conditions were present at that time, then the petition for annulment is denied, but if they find that one of these conditions was indeed missing at the time of the wedding, then the sacrament of marriage never truly existed.
Judges examine all the evidence and make a decision based on their interviews and documents. Some people might think that like a divorce, once an annulment is applied for, it is all but a formality, and that it will be approved once the proper processes have been carried out. However, this is not the case, because the tribunal is not determining if the marriage can be ended, but rather is determining if the marriage was ever valid. If they find no evidence that any of the five conditions were missing from the marriage, then they will deny the appeal for an annulment. The process assumes that the marriage was always valid, so they must find some positive evidence that something necessary was missing.
Something else that is misunderstood is that this process must be undergone by non-Catholics as well who are divorced and want to marry a Catholic. The Church recognizes the validity and permanence of every marriage, even those contracted by non-Catholics. Therefore, if a Jew marries in a temple, or a Lutheran marries in his church, then those marriages are valid and permanent in the eyes of the Church. Such a person would need to receive an annulment in order to validly marry a Catholic before their previous spouse had died.
Each diocese has its own marriage tribunal and determines cases pertaining to those marrying within its diocese. The exact process for applying for an annulment will vary by diocese, so it is important to contact them when initiating the process.