concurring in result in part and concurring in part.
The majority finds that the word “deception” as used in section 407.020.1, RSMo 1986, does not go beyond common law fraud. If one were writing on a clean slate, this determination would be proper and even desirable. However, this finding ignores the history of the statute.
I.
The majority opinion references the history of the statute in discussing the “capacity to deceive” standard. Until 1986, Missouri law incorporated the meaning of federal law rather than common law to interpret “deception.” § 407.020(1), RSMo 1978. In 1986, the legislature removed the reference to federal law and authorized the attorney general to promulgate regulations setting the scope of Missouri’s law and the meaning of the words used. In 1990, the attorney general *604promulgated regulations explaining that the statute prohibits “a representation or statement of fact in an advertisement that is false or has the capacity to mislead prospective purchasers.” The current federal standard is a new interpretation which prohibits a misrepresentation that is likely to mislead a consumer acting reasonably under the circumstances and that is material (i.e., is likely to lead to injury). In re Cliffdale Associates, Inc., 103 F.T.C. 110, 164 (1984); accord Kraft, Inc. v. F.T.C., 970 F.2d 311, 314 (7th Cir.1992).
It is clear that when the legislature removed the reference, to federal law from the statute the legislature intended to break with the existing federal interpretation. It is equally clear that by leaving the development of standards to the attorney general the legislature did not intend to revert to the common law interpretation. What is not clear is what standard was intended to prevail during the four years the attorney general was developing standards. It is unlikely that the legislature contemplated a period as long as four years without regulations. I do not believe it intended that the meaning of the word “deception” would “accordion” in and out as the majority opinion holds, contracting to common law fraud pending the development of regulations by the attorney general and then expanding to whatever meaning the attorney general finally prescribes for deception once those regulations are adopted. A reasonably intelligent business person would be unsure of the meaning of the term “deception” during this interim period. For that reason, “deception” as used in the statute at the times relevant to this case was unconstitutionally vague.
II.
The analysis above does not change the result in the majority opinion. A defendant whose conduct falls within the “core” of the law may not challenge the law as vague even though the law’s mandate is unclear in other areas. Given the history of the statute, it is clear that “deception” includes common law fraud. The statute is not vague in this respect. It is vague because it is not clear how far it reaches beyond that common law definition. I concur in the remand to the trial court to allow the attorney general the opportunity to prove common law fraud.
III.
I concur in the remainder of the opinion.