When can I disagree with the mara d’asra?
Someone lays claim to another’s possessions. “The majority of poskim rule in my favor,” the claimant avers. The current owner counters that there is a halachic opinion in his favor, and majority or minority is irrelevant: “Kim li—I am of this opinion!” According to halachah, the item is indeed his, free and clear—the rule of chazakah (presumptive ownership) is such that the Beis Din has no right to exhort from the muchzak (one who has something in his possession) based on majority opinion.
One exception to this rule is if the current owner’s statement is countermanded by the mara d’asra (local rav). His psak (halachic ruling) overrides precedent; the strength of the mara d’asra is mid’oraysa (from the Written Torah), prevailing over all other halachic opinions.
Many of the rules that apply to arguing with a rebbe (teacher) as outlined by poskim—those that are bound with kevod haTorah (the Torah’s honor) and kevod rabbo (respect due to a Rabbi)—are also said to apply to the mara d’asra. And more so: since the mara d’asra has been accepted by the majority of the community, his psak attains a status that even if most opinions disagree with a particular psak, it must be upheld.
(There are harsh words put forth by halachic authorities regarding someone who undermines the mara d’asra’s authority, as it can be viewed as arguing against the power of the Torah—and applies even in a situation where the rav who has proven himself to be a Torah scholar inadvertently errs.)
The binding nature of the mara d’asra’s psak applies in all Torah matters, even when its parameters veer towards worldly concerns or public policy, subjects outside the direct realm of halachah.