While discussing the validity of a sale when the original owner was coerced to sell, the Gemara suggests comparing it to a case of divorce.
According to Torah law only the husband can act to divorce his wife; the wife does not have the power to create a divorce. The Gemara in Gittin (88b) teaches that there are exceptions. If a beit din forces the husband to give a get (write of divorce), the divorce will take effect. If it is a non-Jewish court that forces him to give a get, no divorce takes place. If, however, the Jewish court rules that the husband should divorce his wife, but they do not have the power to force him to give a get, they can turn to the secular courts and arrange for them to force him to follow their ruling.
The Talmud Yerushalmi considers the possibility that a Jewish court will only force someone to grant a divorce if the marriage is a forbidden union (for example, a kohen who married a divorcee). The Yerushalmi’s conclusion, however, is that the court can make this decision for other reasons, as well, e.g. if he behaves inappropriately towards his wife.
The Rambam (Mishneh Torah, Hilkhot Geirushin, 2:20) asks how the beit din could force someone to offer a get – shouldn’t he be considered an anoos (someone forced to perform an action against his will) – whose actions are considered null and void? The Rambam explains that the idea of anoos is that a person is forced to do something that he is not obligated to do. Someone who is obligated to perform a certain action – for example, if he is instructed by the beit din to perform that action – cannot be considered forced against his will to do it, since we believe that every Jewish person wants to do what is right and just. Therefore we perceive the situation as being different than what it appears to be – really this individual wants to give the get, and it is his yetzer ha-ra – his evil inclination – that is keeping him from doing the right thing. Thus, forcing him to agree that he desires to give the get, in actuality is allowing him to do what he really wants to do.