(dissenting).
[¶ 21.] I would affirm the summary judgment granted by the trial court and as such, I respectfully dissent.
[¶ 22.] The material facts to this case are not in dispute. The elevator which had contracted for delivery of the grain was insolvent. On November 6, 1995, Atwood orally stated it would subsequently guarantee payment in writing on behalf of the elevator on November 20, 1995. Atwood, without notice, orally revoked its promised guarantee. Ten days later, on November 30, 1995, Atwood drafted a letter sent to the Chairman of the Board of the elevator stating it would “guarantee” payment. All but one of the farmers never got a copy of this letter. The farmers never delivered the full amount of the grain contracted for delivery.
[¶ 23.] The specific relief sought by Atwood.
[¶ 24.] Procedurally, in the circuit court both Atwood and the farmers filed cross-motions for summary judgment. As such, Atwood argued to the circuit court backed up by its affidavits and legal arguments, there was no question of fact as to the farmers’ liability for breach of contract. The farmers agreed summary judgment was appropriate, but differed with Atwood as to which party was entitled to judgment as a matter of law. On appeal to this Court, Atwood framed as its sole issue:
Are the defendant farmers relieved from their obligation to deliver corn and soybeans to the insolvent buyer, Farmers Elevator of Eden, when the plaintiff, the elevator’s financer, offered to pay for the corn and soybeans?
Now, the Majority would give Atwood something it did not even seek once it filed its summary judgment motion in the circuit court and subsequently in its appellate brief: a trial to determine questions of fact. Atwood’s request for relief in its brief states, “[t]he trial court’s order granting the defendant farmers summary judgment should be reversed with directions to enter judgment for plaintiff, Atwood-Kellogg in the sum of $128,-952.72.” After letting the farmers counter this argument in their reply brief, Atwood apparently sensing it would not prevail on its demand for outright judgment, now for the first time discovered that a question of fact really might exist after all and it was entitled to either outright judgment on its behalf or if not, a trial on the merits.
A party to an action may not make a voluntary decision concerning a trial tactic and then when they find themselves in an undesirable position as a result of that legal posture, attempt to proceed in a subsequent inconsistent manner. Judicial estoppel bars such gamesmanship.
Gregory v. Solem, 449 N.W.2d 827, 832 n. 8 (S.D.1989) (citing Federal Land Bank of Omaha v. Johnson, 446 N.W.2d 446 (S.D.1989)). See also Estes v. Millea, 464 N.W.2d 616, 619 n. 3 (S.D.1990).
[¶ 25.] Notice to Atwood of farmer’s refusal to deliver grain.
[¶26.] The Majority errs when it concludes there exists a question of fact as to whether under SDCL 57A-2-702 and 57A-2-609(1) the farmers provided Atwood with sufficient notice, either written or otherwise, that they would withhold delivery of their crops unless payment was made in *755“cash.”5 Atwood admitted it was fully aware the farmers were suspending performance until receipt of assurances. John Case, President of Atwood stated in an affidavit:
Despite the lack of a written demand of adequate assurance of due performance from the defendants, on behalf of Atwood-Kellogg company, I provided such assurances pursuant to my November 29, 1995, letter to Myron Steiner, President of Farmers Elevator Company.
[¶ 27.] That letter further makes it clear Atwood was well aware of the farmers’ demands for further deliveries given the insolvent status of the elevator:
There’s been some discussion about whether or not your patrons will be paid if they delivered corn on contracts after November 30, 1995. To my knowledge, all patrons delivering on contracts in November have been paid. Atwood-Kellogg will guarantee6 that patrons delivering corn on contracts after November 30,1995 will also be paid.
Thus, as in AMF, Inc. v. McDonald’s Corp., 536 F.2d 1167, 1170-71 (7th Cir.1976), there is sufficient compliance with SDCL 57A-2-609 in that all parties had a clear understanding the fanners had suspended performance until they received adequate assurances of due performance from Atwood.
[¶ 28.] Did Atwood offer to pay for the grain in “cash?”
[¶ 29.] As to the merits of the dispute, I agree with the majority that SDCL 57A-2-702 is the controlling statute. It states in part where the buyer is insolvent, the seller may “refuse delivery except for cash including payment for all goods theretofore delivered under the contract, and stop delivery under this chapter (57A-2-705).” (emphasis added). Thus the question is whether the document authored by Atwood can somehow be considered “cash.”7
[¶ 30.] Our code does not define what constitutes “cash.” However SDCL 23A-43-3(5) makes it clear that “cash” is different than a bail bond which is in effect a guarantee for a criminal defendant’s appearance. Compare with the language of the Atwood letter that states in part, “Atwood-Kellogg will guarantee that patrons delivering corn on contracts after November 30, 1995 will also be paid.” (emphasis added).
[¶ 31.] Instructive is our decision in Dale v. Felton, 365 N.W.2d 1 (S.D.1985). Therein Dale entered into a document en*756titled a “Cash Farm and Ranch Lease” for the “annual cash rent” of $8,000. When Dale ran into financial trouble he tried to substitute a promissory note for the “cash” payment. In upholding summary judgment against Dale we held his attempt to substitute a promise to pay in the form of a note was not a “legally sufficient compliance with the terms of the lease” which demanded payment to be made in cash. Dale, 365 N.W.2d at 3. In so doing we reasoned:
“cash” in its strict sense refers to coins and paper money. It is also used, less strictly, to mean not only money but also checks and demand deposits in banks and savings institutions. Stewart v. Selder, 473 S.W.2d 3, 8 (Tex.1971). A promissory note, even if fully secured, does not constitute cash or its equivalent. Don E. Williams Co. v. Comm’r of Internal Revenue, 429 U.S. 569, 97 S.Ct. 850, 51 L.Ed.2d 48 (1977); Battelstein v. Internal Revenue Service, 611 F.2d 1033 (5th Cir.1980). Dale’s February 7, 1983 promise to pay was nothing more than a promissory note secured by collateral. In no reasonable meaning of that word could it be considered the equivalent of cash.
Id. (emphasis added). Atwood’s letter is even more deficient than Dale’s as it merely promises to pay but is secured by no collateral.
[¶32.] Cash is “money or currency issued by lawful authority intended to pass and circulate as such.” Lee v. State Department of Public Health, 480 S.W.2d 305, 309 (Mo.App.1972) (other citations omitted). “The word cash ... means ready money and does not include a promise to pay in the future ...” Sun Finance & Loan Co. v. H.M. Ferguson, Inc., 162 N.E.2d 880, 881 (Ohio Ct.App.1959) (per curiam). Art 1 § 8 of the United States Constitution reserves unto the Federal Government the exclusive power to “coin money, regulate the value thereof ...” Pursuant to that authority Congress passed PL 89-81, § 102 which states:
All coins and currencies of the United States (including Federal Reserve notes and circulating notes of Federal Reserve banks and national banking associations), regardless of when coined or issued, shall be legal tender for all debts, public and private, public charges, taxes,8 duties, and dues.
[¶ 33.] A more expansive view of the definition of cash is taken by other courts. However, even under this expanded definition the term “cash” still excludes checks, drafts and negotiable instruments in any other form. It means United States currency. Certified checks, bank drafts and cashier’s checks may, in appropriate circumstances, constitute an exception when drawn upon or issued by banks the existence and solvency of which are known to the person accepting them. Buckeye Development Corp. v. Brown & Shilling, Inc., 243 Md. 224, 220 A.2d 922, 925 (1966).
[¶ 34.] Whether one adopts a strict definition of cash to be synonymous with “legal tender” or includes other bank guaranteed forms of payment, under either definition, the document drafted by Atwood is not “cash.” It is no more than a unilateral promise to pay which is based solely on its financial viability and the on-again, off-again and on-again self-declared willingness of Atwood to honor its promise to pay.
[¶ 35.] Dale supports summary judgment in favor of the farmers as there we held “this is the type of case that is apt for *757disposition by motion for summary judgment, involving as it does only questions regarding the adequacy of payment under a written instrument.” 365 N.W.2d at 3. Here, since Atwood’s unsecured promise to pay is not “cash,” it does not meet the legal requirements of SDCL 57A-2-702 to demand delivery from the farmers.
[¶ 36.] For the above reasons I wopld affirm the summary judgment of the trial court and therefore respectfully dissent.
. SDCL 57A-2-609(l) states in part where reasonable grounds arise in the seller as to the solvency of the buyer, the seller "may in writing demand adequate assurance of due performance ...” As we recently held in State v. Burgers, 1999 SD 140, ¶ 15, 602 N.W.2d 277 ”[w]ith respect to legislative enactments, we have held that the word 'may' in a statute should be construed in a permissive sense unless the context and subject matter indicate a different legislative intent.” (citing Person v. Peterson, 296 N.W.2d 537, 538 (S.D.1980)).
. Even as a purported guarantee this document fails against all farmers except Willard Hill. SDCL 56-1-4 explicitly states, "a guaranty must be in writing ...” Only Hill received a copy of the letter. Despite the fact SDCL 56-1-4 was raised as a defense by the farmers, Atwood makes no attempt to argue its guarantee falls into one of the exceptions to a writing contained in SDCL 56-1-6 through 56-1-9. Furthermore, this "guarantee” by its terms, limits itself to corn and thus did not “guarantee” contracts for the delivery of soybeans entered into by the farmers.
.This issue is relegated to one sentence in Atwood’s eight page brief: "instead, since they [farmers] were guaranteed payment, they were, in effect, offered ‘cash’ and were obligated to deliver, and they would have received what they contracted for.” This statement is made without any supporting authority whatsoever and therefore under our appellate rules, the entire argument should be deemed abandoned. Failure to cite supporting authority is a violation of SDCL 15-26A-60(6) and should result in the issue being waived. State v. Pellegrino, 1998 SD 39, ¶ 22, 577 N.W.2d 590, 599.
. Perhaps no clearer example of the fact this Atwood document does not equate with cash comes from what would happen if the farmers attached it to their income tax returns as payment and sent them into the Internal Revenue Service for processing.