(dissenting).
I respectfully dissent. I would conclude that Hy-Vee may avoid the 3-year sanction by proof that its acceptance of the voucher was the product of the mutual mistake of the parties to the sale. Because there are genuine issues of material fact concerning Hy-Vee’s claim of mutual mistake, I would reverse the court of appeals and remand to MDH for hearing.
The WIC tobacco rule mandates a 3-year disqualification on a WIC vendor for “[o]ne incidence of the sale of * * * tobacco products in exchange for food instruments.” 7 ‘ C.F.R. § 246.12(Z )(l)(iii)(A). But the federal rule does not define the word “sale,” and the state’s counterpart rule does not define the word “provide.”
*191The court of appeals reconciled the parties’ arguments by viewing the word “sale” in isolation and concluding that a sale does require intent but that such intent need only be proven by the parties’ objective conduct (i.e., the presentation of the item, the calculation of the price, the offer and acceptance of payment and the delivery of the item). Hy-Vee Food Stores, Inc., 2004 WL 2340189 at *2. I agree that the word “sale” implies an element of intent and that such intent can be proven by the objective facts and need not explore the subjective thoughts of the parties to the transaction. See, e.g., Minn.Stat. § 336.2-204(1) (2002) (“contract for sale of goods may be made in any manner sufficient to show agreement, including conduct by both parties which recognizes the existence of such a contract”); Barker v. Allied Supermarket, 596 P.2d 870 (Okla.1979) (holding sale occurred under Uniform Commercial Code when supermarket customer placed item in shopping cart).
But the WIC tobacco rule does not use the word “sale” in isolation. In order to give meaning to all words in the rule, “sale” must be read in conjunction with the words “in exchange for food instruments.” Hy-Vee argues that the cashier and customer both intended for tobacco to be sold in exchange for cash, not for a WIC food instrument, and that their mutual mistake as to method of payment invalidated the transaction for WIC disqualification purposes. Ordinarily, as the majority notes, the method of payment would not be material to the accomplishment of a sale. But here, the violation depends precisely on the method of payment. No regulation is violated by the mere sale of cigarettes. The violation only occurs if the proscribed method of payment (exchange for food instruments) is used. Thus the question arises whether the intent element implicit in a sale also applies to the method of payment where that method is made material to the completion of the sale.1 And, if so, may the vendor attempt to prove that there was no intent to use a WIC voucher as the method of payment by showing that the presentation and acceptance of the WIC voucher for a prohibited, item was the product of a mutual mistake?
In Winter v. Skoglund, 404 N.W.2d 786 (Minn.1987), we endorsed the framework for analyzing mutual mistake that is provided in the Restatement (Second) of Contracts § 152 (1981):
(1) Where a mistake of both parties at the time a contract was made as to a basic assumption on which the contract was made has a material effect on the agreed exchange of performances, the contract is voidable by the adversely affected party unless he bears the risk of the mistake under the rule stated in § 154.
(2) In determining whether the mistake has a material effect on the agreed exchange of performances, account is taken of any relief by way of reformation, restitution, or otherwise.
In Winter, we found mutual mistake when two parties both entered a contract with the erroneous beliefs that a third party already had been bound in the agreement. 404 N.W.2d at 793. We held that “[t]his was a basic assumption on *192which the contract was made and its falsity would materially change the bargain.” Id. Five years earlier, in Gartner v. Eikill, we found mutual mistake when parties to a property sale erroneously believed that the property could be developed. 319 N.W.2d 397, 399 (Minn.1982). We concluded that a mistake regarding the viability of property development “went to the very nature of the property.” Id.
The facts presented here do not fit precisely within the mutual mistake framework because the mistaken tender of payment arguably took place after the customer had accepted Hy-Vee’s offer of groceries. See Restatement (Second) of Contracts § 50(2) (1981) (“[acceptance by performance requires that at least part of what the offer requests be performed or tendered”). In addition, there was no mistake as to the nature of the goods being sold. But I agree with Hy-Vee that, because the use of a “food instrument” is the determinative fact under the WIC tobacco rule, the method of payment goes to the “very nature” of the transaction. See Gartner, 319 N.W.2d at 399. Accordingly, I would conclude that a vendor who accepts a WIC voucher in payment for cigarettes may attempt to prove that the transaction did not violate the WIC tobacco rule because the use of the voucher was the result of the mutual mistake of the parties.2
I reach that conclusion, in part, by applying a strict construction to the WIC tobacco rule based on the severity of the sanction. In contrast to the WIC tobacco rule, which imposes disqualification for a single incident in violation, other WIC rules require proof of a pattern or series of what appear to be regarded by the USDA as equally serious violations before a mandatory disqualification is imposed. 7 C.F.R. § 246.12(l)(iii)(B)-(F) (addressing vendor overcharges, charging for food that participant does not receive, providing credit or nonfood items, claiming reimbursement for sales that exceeds store’s documented inventory, and receiving, transacting, or redeeming vouchers “outside of authorized channels”); 7 C.F.R. § 246.12(l)(iv) (addressing provision of unauthorized food items). I am reluctant to imply administrative agency authority to impose more severe sanctions where express authority to do so is not clear. See Pet. of Northern States Power Co., 414 N.W.2d 383, 388 (Minn.1987) (holding that “less harsh result” was warranted when Minnesota Public Utilities Commission lacked express authority to dismiss a regulatory proceeding).
My conclusion is reinforced by the history surrounding the adoption of the WIC tobacco rule. The rule was added in 1998 as a part of a larger USDA effort to “mandate uniform sanctions across States for the most serious WIC Program vendor violations, including seven specific WIC Program violations * * *.” 63 Fed.Reg. 19,415 (Apr. 20, 1998). USDA explained that “[t]he implementation of these mandatory sanctions is intended to promote WIC and [Food Stamp Program] coordination in the disqualification of retailers and ven*193dors who violate program rules.” Id. at 19,416. At the time, there was a “major movement in the USDA to control fraud and abuse in the WIC Program.” Brandi M. King, Note, Separating Food from Culture: The USDA’s Failure to Help Its Culturally Diverse WIC Population, 6 Drake J. Agrie. L. 223, 237 (2001). In a report to Congress about the changes, the General Accounting Office observed that vendors’ “intentional” and “deliberate” actions were the chief concern:
Vendor fraud or abuse is an intentional or deliberate action taken to violate program regulations, policies, or procedures. Actions include, but are not limited to, accepting food vouchers for cash, which is known as trafficking, or providing credit toward the purchase of unauthorized items; giving cash or credit for returned food items that were purchased with food vouchers; altering food vouchers or accepting expired vouchers; charging more than the shelf price or exceeding the maximum price allowed by WIC; or charging for food that the participant does not receive.
Food Assistance: Efforts to Control Fraud and Abuse in the WIC Program Can Be Strengthened (United States General Accounting Office, Report to Congressional Committees, August 1999), at 17, available at http://www.fns.usda .gov/wic/resources/ Efforts.pdf (last visited Sept. 29, 2005).
The majority relies on USDA’s definition of “vendor violation” for guidance in gauging the intent behind the WIC tobacco rule. A “vendor violation” is defined as “any intentional or unintentional action of a vendor’s current owners, officers, managers, agents, or employees (with or without the knowledge of management) that violates the vendor agreement or Federal or State statutes, regulations, policies, or procedures governing the Program.” 7 C.F.R. § 246.2. In recommending Hy-Vee’s disqualification, the ALJ relied in part on this definition, and the court of appeals concluded that the regulatory history of the “vendor violation” definition “expressly provides that state agencies are not required to show that a vendor intended the violation.” Hy-Vee Food Stores, Inc., 2004 WL 2340189 at *2.
But I find the history of this definition to be contradictory. It is true that when USDA proposed this definition of “vendor violation” in 1999, it explained that vendors were to be held accountable for “deliberate” violations as well as “inadvertent” errors because both “ha[d] the same negative effect on the Program.” 64 Fed. Reg. 32,316 (June 16, 1999). But, in the same explanation, USDA observed that “this does not mean that a minor unintentional action by a cashier without management knowledge would result in disqualification.” Id. This observation states the ultimate conclusion that is to be reached by applying the definition to a specific set of facts — that no disqualification will result, and a vendor violation does not occur, when a cashier commits a “minor unintentional” error without management knowledge. This ultimate conclusion is instructive on how the definition of vendor violation should be applied here because these are the precise facts — an unintentional error — that the ALJ assumed to be true for purposes of summary disposition.
This contradiction in the “vendor violation” definition history was underscored when the rule was being made final late in 2000. USDA then observed that “limiting the scope of vendor overcharges only to those that are intentional or fraudulent would undermine the integrity of the WIC Program,” but again stated that “[w]e want to emphasize that not all vendor violations will give rise to a vendor sanction” and that an “inadvertent mistake” may not *194trigger a sanction. 65 FecLReg. 83,260-61 (Dec. 29, 2000).3
Of course, as Hy-Vee argues, any attempt to use the definition of “vendor violation” to determine whether a violation has occurred is necessarily circular — it presumes the existence of the underlying violation that is in question. Moreover, the term “vendor violation” is not used in the WIC tobacco rule. Where it is used in other rules, an array of possible sanctions is provided. For example, the sanctions for “vendor violations” that states must describe in vendor contracts include withholding of payment of vendor claims, “administrative fines, disqualification and civil money penalties in lieu of disqualification.” 7 C.F.R. § 246.12(h)(3)(ix), (xviii) (2005). Thus, although the definition of vendor violation contemplates strict liability, the administrator is given significant discretion when choosing the sanction.4 All of this suggests that the definition of vendor violation has no application here.
I realize that USDA and MDH have strong interests in ensuring that WIC-eligible women and children are not exposed to tobacco or alcohol. But given the ambiguities and contradictory, comments in the promulgation history, I am not prepared to characterize a single, inadvertent sale of tobacco in exchange for a WIC voucher as a violation that triggers the 3-year mandatory disqualification.
I would hold that when a WIC vendor appeals to MDH from a mandatory 3-year disqualification under 7 C.F.R. 246.12(Z )(l)(iii)(A), the vendor may show, as an affirmative defense, that the vendor’s acceptance of a WIC voucher in exchange for tobacco products was the result of a mutual mistake of the parties to the transaction. See Theisen’s, Inc. v. Red Owl Stores, Inc., 309 Minn. 60, 65, 243 N.W.2d 145, 148 (1976) (party seeking reformation of written instrument because of mutual mistake bears burden of proof); see also Bryan v. Moore, 863 A.2d 258, 260 n. 4 (Del.Ch.2004) (characterizing mutual mis*195take as affirmative defense); Smith v. First Choice Services, 158 N.C.App. 244, 580 S.E.2d 743, 748 (2003) (same). Because Hy-Vee made such a showing, sufficient to avoid summary disposition, I would determine that the grant of summary disposition in favor of MDH was affected by an error of law.
. The majority suggests that the appropriate framework for this question is to decouple the words of the rule into three separate elements: (1) the sale, (2) the object of the sale, and (3) the method of payment, confining the relevance of intent to only the first such element. But the rule does not separate the words in such a way, and this analytical framework does not shed any light on the question of whether the method of payment is material to the type of sale with which the rule is concerned. I read the words to be dependent, not independent, parts of the rule.
. I acknowledge that mutual mistake is more commonly used as a contract doctrine that may apply when a party to a contract seeks to void it. But I would conclude that the underlying principles of the mutual mistake doctrine provide an appropriate framework, by analogy, both for addressing the intent elements implicit in the rule and allocating the burden of proof concerning those elements. Moreover, the affidavits of the parties to the transaction suggest that each would gladly void the transaction and substitute cash as the method of payment. I see no purpose being served by any requirement that the parties go through formal steps of rescission in order to avail themselves of the rationale of the doctrine.
. In addition, I question whether this definition of “vendor violation” was meant to be applied outside the context of "overcharges,” for which a “pattern” of wrongdoing is required before a disqualification must be imposed. 7 C.F.R. 246.12(Z )(l)(iii)(C). After USDA published the proposed definitions of "vendor violations” and “vendor overcharges” in the Federal Register, two commenters objected to the use of the word "unintentional” in the definition of vendor overcharges. 65 Fed.Reg. 83,261. In explaining its rationale, USDA observed that "limiting the scope of vendor overcharges only to those that are intentional or fraudulent would undermine the integrity of the WIC Program.” Id. In contrast, when two commenters objected to the use of the word “unintentional” in the definition of "vendor violations,” the USDA responded quite differently:
We acknowledged the complexity of WIC transactions and noted that even with training and supervision, cashiers may occasionally make unintentional errors. We also stated that the State agency has a wide range of actions that it may take as a result of a vendor violation, including assessing a claim, requiring increased training, identifying the vendor as a high-risk vendor subject to compliance investigation, and imposing a sanction.
65 Fed. Reg. 83,260.
. Other uses of the term "vendor violation” provide the vendor with an opportunity to correct the error. See, e.g., 7 C.F.R. § 246.12(k)(2) (2005) ("When the State agency determines that the vendor has committed a vendor violation that affects the payment to the vendor, the State agency must delay payment or establish a claim. Such vendor violations may be detected through compliance investigations, food instrument reviews, or other reviews or investigations of a vendor's operations.”); and 7 C.F.R. § 246.12(k)(3) (2005) (stating that when payment "is delayed or a claim is established, the State agency must provide the vendor with an opportunity to justify or correct the vendor overcharge or other error”).