However, it is also possible that a threshold limiting proportionality may be formulated with regard to capacity. Later in Re B, the High Court stated that increasing the threshold of jurisdiction required for jurisdiction where the expected harm is greatest, according to this argument, results from a clinician`s or court`s desire to be safer.45,49 This means leaving a greater margin of error, if the consequences are serious (Figure 2).50,51 Raising the threshold, of course, also increases the number of cases in which people are wrongly classified as unfit. Then the damage is done because their autonomous desires are not respected. This is another type of harm than not acting in someone`s best interest. Proponents of a margin of error approach must assume that it does not increase in severity based on what is at stake or, if so, that it does not do the same. The court conducted a detailed review of the patient`s medical history and mental state and concluded that her mental abilities were intact. In those circumstances, according to the judgment, proportionality corresponds. There comes a time when a patient`s capacity is such that any decision to refuse treatment must be respected, regardless of the severity of the consequences. Medical commentators have also stressed the need to compromise the “autonomous power of choice” before treatment can be administered or refused without consent.31 However, legal jurisdiction cannot be more or less present. A person has the right or not to have his or her wishes respected with regard to the processing. Doctors, relatives of patients and, in contentious cases, the courts must decide whether that person`s mental capacity is sufficient for legal capacity and whether their stated wishes must therefore be respected if a person`s right to accept or refuse treatment is called into question. Two questions arise.

The humane functioning of psychiatric, medical and geriatric units, where the inability to make legally binding decisions is on the agenda, seems to require a thrifty use of coercion.10,19 The House of Lords` judgment in Bournewood55 that if an incapacitated patient is treated in his or her best interests and raises no objections, no further legal action is required, suggesting that the courts prefer an equally frugal approach to declaring a person incapacitated. Wicclair cites the example of a five-year-old whose parents allow him to choose what he will eat for lunch, unless one of the menu items is life-threatening.56 It is possible, as the balancing and margin of error approaches allow, that the child is legally empowered to make a decision, but not the other. However, it seems more likely that this jurisdiction is the same, but that their parents will want to respect the child`s decisions if it does not lead to harm. The question of whether an increase in the severity of the consequences should lead to a corresponding increase in the mental capacity required for legal jurisdiction is discussed in the first part of the article. The usual conclusion is that he should, with the caveat, that the law`s approach to patient autonomy complicates the relationship. The second part of the paper examines the reasons for the variation in the capacity threshold in this way. The third examines two other considerations relevant to the question whether a person`s wishes with regard to his or her medical care should be taken into account, which affect this practice of shifting the threshold of capacity required for legal jurisdiction in response to what is at stake.