One of the most serious areas of law that is involved here concerns the laws of yichud. A man is not allowed to be alone in a closed room (or any place where they do not fear being disturbed) with a woman, with very few exceptions. One such exception is his wife, and this topic will lead us directly into the first of the opinions on chupah, that of Rambam.

Assuming one of the strictest views on what chupah is, Rambam writes (Hil. Ishut 10:1) that  Jewish wedding chupah occurs when the man brings the woman into his house and has yichud with her. At this point she is considered to be a “nesu’ah” (married woman) and is considered to be his wife for all areas of halacha. He concludes by noting that this seclusion accomplishes the goal of cementing the marriage even if the couple had not yet had relations with each other, so long as they could have done so (“chupah ha-re’uyah l’bi’a“).

This last comment of Rambam is crucial to his overall view. As the Derisha notes, Rambam’s position is based on the perspective that the entire point of the chupah is the relations that will follow. Thus, even if the relations do not occur, as long as it is possible that they could have, the chupah is valid. This becomes an issue in an area that we will only mention briefly here, namely the case of a “chupat nidda,” when the woman is menstruating at the time of the Jewish wedding chupah. Since she is forbidden to any man at that time, there is no possibility for relations to occur, and the two are not fully married and may not be alone with each other until such time as she is pure and they can consummate their marriage (we should note that this is not the view that is followed today).

The Kesef Mishna cites Ran, who is shocked at the view of Rambam. He brings in the gemara in Yevamot 57b, which states clearly that women who are unfit for marriage for whatever reason can still have a valid chupah. Rosh (Ketubot 5:6) also objects to the view of Rambam. He first cites Rabbeinu Channanel and Rif, who agree with Rambam, and then cites Rambam himself. However, he notes that throughout the gemara, whenever the issue of chupah is involved with the ramifications being whether or not a non-kohein woman who is marrying a kohein will be able to eat from terumah (food given to the priests that only they may eat), the question of a chupat nidda is never raised. Thus, says Rosh, there is clearly an assumption that a chupat nidda is valid. To deal more directly with the concerns of Rambam, Rosh notes that so long as the groom enters the chupah with the intentions to consummate the marriage, the chupah is valid even if his wife is then found to be impure (the Magid Mishna agrees with this opinion). Perhaps concerned with the view of Rambam, the Hagahot Ashri notes in the name of the Mordechai that there was the practice to inform the groom before the chupah if his wife was impure. While he does not specify whose view he is following, if he were to be following the view of Rambam, then the chupah would clearly not be valid if the woman were to be impure.