rules are seen as constraints on au- , thority is it helpful to say that the rules do not apply to reconsideration by a trial court. The policies that support adherence to earlier rulings without perpetual reexamination surely do apply [to trial-court rulings], whatever label is used.”). "Law of the case” doctrine, as described in Arizona, embodies principles that work alongside Rule 54(b) of the Federal Rules of Civil Procedure in guiding a court’s discretion when reconsidering issues decided in the same case. 4 . We say "may be inappropriate” rather than “is inappropriate” because the Court in Mead discussed factors that were sufficient to trigger Chevron deference; it did not hold that the absence of these factors necessarily precluded the application of Chevron deference. Id. .(<HOLDING>). Ultimately, Chevron deference applies if
holding that deference  is warranted only when it appears that congress delegated authority to the agency generally to make rules carrying the force of law and that the agency interpretation claiming deference was promulgated in the exercise of that authority and discussing united states v mead corp 533 us 218 22627 121 sct 2164 150 led2d 292 2001 and chevron usa inc v natural res def council inc 467 us 837 84245 104 sct 2778 81 led2d 694 1984 holding that administrative implementation of a particular statutory provision qualifies for chevron deference when it appears that congress delegated authority to the agency generally to make rules carrying the force of law and that the agency interpretation claiming deference was promulgated in the exercise of that authority holding that chevron deference is due only when the agency acts pursuant to delegated authority and the agency action has the force of law holding that chevron deference is due only when the agency acts pursuant to delegated authority holding that an unpublished bia decision that does not rely on precedent for its definition of a contested term does not receive chevron deference because it is not promulgated under the agencys authority to make rules carrying the force of law