The question of whether a Catholic who is divorced can receive Holy Communion without a formal declaration of nullity (an annulment) is a complex matter governed by Canon Law and interpreted through pastoral practice. An annulment is a judgment by a Church tribunal that a marriage was not valid from its beginning due to some impediment or deficiency in consent, form, or canonical impediment. Without such a declaration, the Church presumes the marriage was valid.
Historically, divorced and remarried Catholics were generally prohibited from receiving Communion because the Church views marriage as a lifelong, indissoluble bond. Remarriage after divorce (without an annulment) is considered adultery according to Catholic doctrine, placing the individual in a state of serious sin. This prohibition stemmed from the understanding of the Eucharist as a sign of communion with the Church and its teachings on marriage. However, the Church also emphasizes pastoral care and seeks to minister to individuals in these difficult situations.