DISSENTING OPINION OF
BURNS, C J.I respectfully dissent.
HRS § 706-610(2) (Supp. 1991) states as follows:
A felony defined by any statute of this State other than this Code shall constitute for the purpose of sentence a class C felony, except if another provision of law specifically defines a felony to be of a specified class as defined by this Code, such felony shall be treated for the purpose of sentence as provided by this chapter for that class of felony.
The majority concludes that the greater maximum sentence authorized by HRS § 291C — 12(b) (1985) was not one of HRS § 706-610(2)’s authorized exceptions. I disagree.
Commencing June 17, 1992, HRS § 291C-12(b) expressly categorizes the felony proscribed by HRS § 291C-12(a) as a class B felony. Prior thereto, and on May 21, 1990 when Defendant violated HRS § 291C-12(a) (1985), HRS § 291C-12(b) did not express any alphabetical label for the crime. However, it expressly provided for “imprison[ment of] not more than ten years[.]” Since the maximum prison term for a class B felony is ten years whereas for a class C felony it is five years, HRS § 706-660 (Supp. 1991), the penalty expressly authorized by HRS § 291C-12(b) was a class B penalty.
*343Did HRS § 291C-12(b), prior to its amendment on June 17, 1991, specifically define HRS § 291C-12(b)’s felony to be of a specified class as defined by HRS § 706-660? The majority’s answer is no, because HRS § 291C-12(b) did not then, as it does now, expressly state the alphabetical label “B.” My answer is yes because, when HRS § 291C-12(b) specifically permitted imprisonment of not more than ten years, it thereby specifically defined the felony to be a class B felony. HRS § 706-610(2)’s exception when the “provision of law specifically defines a felony to be of a specified class as defined by this Code” unambiguously means more than “specifically states the alphabetical class” or “specifically classifies as a class A or class B felony.” There is no meaningful difference between a provision that the felony is a class B felony and a provision that the maximum prison term for the felony is ten years.
In my view, the majority’s decision invalidating HRS § 291C-12(b)’s authorization of “imprison[ment of] not more than ten years” is, to quote the majority opinion, “inconsistent not only with the legislature’s intent but also with the general rule that a statute should be interpreted to give it effect and to avoid a construction that would render it a vain legislative effort or a nullity.”
Additionally, I disagree that State v. Spencer, 68 Haw. 622, 725 P.2d 799 (1986), is “clearly distinguishable.” When Spencer was decided and prior to January 1, 1987, HRS § 706-610(2) (1985) provided in its entirety as follows: “Notwithstanding any other provision of law, a felony defined by any statute of this State other than this Code shall constitute for the purpose of sentence a class C felony.” In other words, when Spencer was decided, HRS § 706-610(2) did not permit any exception. Despite such legislative mandate, the supreme court applied the rule that “where there is a ‘plainly irreconcilable’ conflict between a specific statute and a general statute concerning the same subject matter, the specific statute will be favored,” Spencer, 68 Haw. at 624, 725 P.2d at 800 (citation omitted), and enforced HRS § 291C-12(b) (1985) rather *344than HRS § 706-610(2). The supreme court did not discuss the legislative history of HRS § 706-610(2).
As an inferior court, if there is a “plainly irreconcilable” conflict between HRS § 291C-12(b) and HRS § 706-610(2), we are obligated to follow the rule in Spencer and favor HRS § 291C-12(b). See Robinson v. Ariyoshi, 65 Haw. 641, 653, 658 P.2d 287, 297 (1982) (where a principle has been passed upon by the court of last resort, it is the duty of all inferior tribunals to adhere to the decision (quoting Kapiolani Estate, Ltd. v. Atcherley, 21 Haw. 441, 454 (1913) (citations omitted)).
Accordingly, I would affirm the sentence imposed by the circuit court.