BOLIN, Justice.

These parties have been before this Court previously. See Prince v. Poole, 935 So.2d 431 (Ala.2006) ("Prince I"). Because the facts and procedural history of Prince I are necessary for a complete understanding of the issues presented by this appeal, we quote extensively from the detailed statement of the facts and procedural history in Prince I, and we use the terms defined therein as defined terms in this opinion:

                   "`I. Fee Splits

  "`James H. Seale                       10%   .100
    Silas G. Cross, Jr. &
    Erby J. Fischer                8% of 90%   .072
    Phil Poole                    30% of 90%   .270
    Robert F. Prince              26% of 90%   .234
    [Pearson appellants]
      and H. Gregory
      Pearson, P.C.               36% of 90%   .324
                                             ______
    Total                                     1.000

Prince I, 935 So.2d at 433-42 (footnotes omitted).

Pearson and Prince argued on appeal that they were entitled to introduce parol evidence because, they said, the February 15 letter did not contain a merger clause and was not intended to be a complete integration of the parties' agreement. Pearson and Prince argued that the parties' agreement was partly oral and partly written and that the February 15 letter effected only a partial integration of the parties' agreement and was not intended to be the complete expression of the parties' agreement. Therefore, Pearson and Prince contended that parol evidence was admissible as to the oral terms of the parties' agreement. Prince I, 935 So.2d at 433.

Specifically, Pearson and Prince argued that the express terms of the February 15 letter did not place the obligation on anyone to actually prosecute the Moundville gasoline litigation. Thus, Pearson and Prince contended that the terms of the parties' respective obligations to prosecute the Moundville gasoline litigation were omitted from the February 15 letter and that they were entitled to produce parol evidence as to those terms. Poole responded by arguing that the February 15 letter was an unambiguous contract and, therefore, that parol evidence was inadmissible to vary or add to its terms. Prince I, 935 So.2d at 433.

The parol evidence sought to be introduced by Pearson and Prince suggested that Poole had assumed certain obligations with regard to the prosecution of the Moundville gasoline litigation that were not mentioned in the February 15 letter and that he had failed to perform those obligations. Pearson argued that Poole had agreed to assist in working on the Moundville gasoline litigation and to work to end the dissolution dispute with Prince's former firm. However, Pearson contended that after the February 15 letter, Poole neither worked on the Moundville gasoline litigation nor worked to end the dissolution dispute.

Prince testified in his affidavit that the February 15 letter was only a part of the parties' overall agreement and that Poole was to refer new cases in the Moundville gasoline litigation, assist with State agencies, and be available to assist with jury selection and at trial of the Moundville gasoline litigation.4 However, Prince testified that Poole did not perform any of those obligations after the February 15 letter was written. Prince I, 935 So.2d at 446.

Poole disputed Pearson and Prince's claims that he assumed obligations other than those expressed in the February 15 letter. Poole contended that he was obligated only to include in the pooled cases any Moundville gasoline litigation that happened to come his way and that there was no evidence indicating that he had breached that requirement. Prince I, 935 So.2d at 446.

In reversing the summary judgment entered by the trial court in favor of Poole, this Court held that the February 15 letter was not a complete expression of the parties' agreement and did not completely integrate the parties' agreement because it omitted terms relative to the parties' obligations to prosecute the Moundville gasoline litigation. Thus, this Court held that Pearson and Prince were entitled to introduce parol evidence as to those omitted terms. Prince I, 935 So.2d at 451.

As for the issue whether Poole had assumed obligations not expressed in the February 15 letter, this Court stated:

Prince I, 935 So.2d at 446-47 (footnote omitted). Additionally, this Court concluded that questions of fact existed as to whether the parties intended their agreement to be a referral arrangement or an association arrangement and, if Poole did assume obligations under the parties' agreement, whether the parties intended Poole's performance of those obligations to be a condition precedent to his entitlement to fees recovered in the Moundville gasoline litigation. This Court stated:

Prince I, 935 So.2d at 451-52 (footnote omitted). On January 27, 2006, we reversed the summary judgment and remanded the case.

On Remand

On March 14, 2007, Prince moved the trial court for a summary judgment as to Poole's counterclaims asserting breach 011 of contract, fraud, suppression, breach of a fiduciary duty, and conversion. As to the breach-of-contract claim, Prince argued that Poole could not satisfy the elements of a contract because he could not establish his own performance under the agreement. Prince contended that Poole did no work in connection with the prosecution of the Moundville gasoline litigation after February 15, 2000, and that the Moundville plaintiffs had disavowed him as their counsel. Prince also argued that Rule 1.5(e), Alabama Rules Professional Conduct, prohibits Poole from receiving a fee on a case that he has not referred, has not done a proportionate amount of work on, and does not have the consent of the client to participate in. Prince contended that at most Poole was entitled to a quantum meruit recovery only for his contribution to the Moundville gasoline litigation.

On March 28, 2007, Pearson moved the trial court for a summary judgment as to Poole's counterclaims and also joined Prince's motion for a summary judgment. Pearson argued in his motion that he was entitled to rescind the alleged February 15 letter agreement based on a failure of consideration by Poole. Pearson also argued that he was entitled to terminate Poole's association based on the continued fighting between Prince and Poole because it was detrimental to the interests of Pearson and of his Moundville gasoline litigation clients.

On April 18, 2007, Poole responded to Prince's and Pearson's motions for a summary judgment. Poole argued, as to the breach-of-contract claim, that the February 15 letter was a valid and binding contract supported by consideration and that he met all of his obligations as to the Moundville gasoline litigation under the February 15 letter. Poole also argued that the February 15 letter did not violate Rule 1.5 of the Alabama Rules Professional Conduct.

Both Prince and Pearson replied to Poole's response in opposition to their motions for a summary judgment. Pearson also moved the trial court to strike portions of Poole's affidavit filed in support of his response in opposition to the motions for a summary judgment.

On June 28, 2007, the trial court entered an order granting Prince's and Pearson's motions for a summary judgment as to Poole's counterclaims of promissory fraud, fraudulent suppression, conversion, and breach of fiduciary duty. The trial court denied the motions for a summary judgment as to Poole's breach-of-contract counterclaim, finding that substantial evidence existed indicating that

On August 17, 2007, Poole moved the trial court for a summary judgment on Pearson's claim of tortious interference with business relations. On August 31, 2007, Pearson filed a response in opposition to Poole's motion.

On February 4, 2008, Poole moved the trial court for a summary judgment on his breach-of-contract claim. Poole argued in support of his motion that he had fulfilled the contractual obligations regarding the Moundville gasoline litigation under the February 15 letter; that the February 15 letter is a valid contract supported by consideration; that the February 15 letter complies with Rule 1.5, Ala. R. Prof. Cond.; and that, because the February 15 agreement was an express agreement, any argument based on a quantum meruit recovery must fail. Both Pearson and Prince filed responses in opposition to Poole's motion for a summary judgment.

On March 31, 2008, Prince moved the trial court for a summary judgment on Poole's breach-of-contract claim. Prince argued that Poole could not satisfy the elements of a contract because he could not establish his own performance under the agreement. Prince also argued that Poole's interpretation of the February 15 letter violated the requirements of Rule 1.5(e), Ala. R. Prof. Cond., rendering the agreement unenforceable. Additionally, both Pearson and Prince moved the trial court to strike Poole's affidavit filed in support of his motion for a summary judgment.

On May 8, 2008, Prince supplemented his motion for a summary judgment with this Court's decision in White Sands Group, L.L.C. v. PRS II, LLC, 998 So.2d 1042 (Ala.2008), and argued that the terms of the February 15 letter were too indefinite because the letter failed to identify or specify the obligations of the parties with regard to who was to perform the work on the Moundville gasoline litigation.

Following a hearing on September 11, 2008,5 the trial court, on October 8, 2008, entered a summary judgment in favor of Pearson and Prince on Poole's breach-of-contract claim and denied Pearson and Prince's motion to strike Poole's affidavit. Relying on this Court's decision in White Sands Group, L.L.C., supra, the trial court concluded that Poole had failed to produce substantial evidence showing that an enforceable contract existed between the parties. As an alternative ground for entering a summary judgment in favor of Pearson and Prince, the trial court concluded that even if a contract existed between the parties, it would be unenforceable as violative of Rule 1.5, Ala. R. of Prof. Cond.

Poole appealed following the denial by operation of law of his postjudgment motion. On August 31, 2009, this Court dismissed the appeal as being from a nonfinal judgment and remanded the case to the trial court.6 On remand, the parties jointly moved the trial court to certify the October 8, 2008, judgment as final pursuant to Rule 54(b), Ala. R. Civ. P. On November 19, 2009, the trial court granted the joint motion and entered an order certifying the October 8, 2008, summary judgment as final pursuant to Rule 54(b), Ala. R. Civ. P. Poole timely filed his notice of appeal on December 22, 2009.

Gooden v. City of Talladega, 966 So.2d 232, 235 (Ala.2007) (quoting Prince I, 935 So.2d at 442, quoting in turn Dow v. Alabama Democratic Party, 897 So.2d 1035, 1038-39 (Ala.2004)).

Discussion

1. Law-of-the-Case Doctrine

Poole argues that the law-of-the-case doctrine precluded a determination by the trial court on remand that the parties' alleged February 15 letter agreement was void for indefiniteness of its terms because, he says, this Court had already determined in Prince I that there were "disputed issues of fact" concerning certain terms of "the parties' agreement." Prince I, 935 So.2d at 452. Regarding the law-of-the-case doctrine, this Court has stated:

Bagley ex rel. Bagley v. Creekside Motors, Inc., 913 So.2d 441, 445 (Ala.2005).

In Prince I, Poole moved the trial court for a summary judgment as to his own breach-of-contract claim. The trial court entered a summary judgment in favor of Poole finding that there was no genuine issue of material fact as to Poole's breach-of-contract claim and that Poole was entitled to a judgment as a matter of law on that claim. Pearson and Prince appealed from the summary judgment in favor of Poole on the breach-of-contract claim.

In addressing the merits of the summary judgment in favor of Poole on his breach-of-contract claim, this Court stated that the summary judgment was appropriate only if there were no disputed issues of material facts relative to any of the elements necessary to establish a breach-of-contract claim, i.e., "`the existence of a valid contract binding the parties in the action, (2) [the plaintiff's] own performance under the contract, (3) the defendant's nonperformance, and (4) damages.'" Prince I, 935 So.2d at 442-43 (quoting Southern Med. Health Sys., Inc. v. Vaughn, 669 So.2d 98, 99 (Ala.1995)). Pearson and Prince challenged the trial court's finding that an enforceable contract existed on the following grounds: (1) consideration and formation, (2) interpretation and parole evidence, (3) performance, (4) equitable issues, and (5) public policy. Pearson and Prince also challenged the summary judgment on two procedural grounds: (1) the denial of Pearson's motion to strike as untimely Poole's supplemental submissions in support of his summary-judgment motion, and (2) the trial court's order granting Poole's motion to strike portions of Prince's affidavit. Prince I, 935 So.2d at 443.

In reversing the summary judgment entered in favor of Poole on his breach-of-contract claim, this Court stated:

Prince I, 935 So.2d at 443 (footnote omitted; emphasis added). In reaching its conclusion, this Court considered only Pearson's and Prince's challenges to the summary judgment based on interpretation, parole evidence, and performance under the contract in order to determine that a question of fact existed as to whether Poole had performed under the February 15 letter, as set out above, which is a necessary element of Poole's breach-of-contract claim. See Prince I, 935 So.2d at 442. This Court's finding of the existence of a genuine question of material fact as to a single element of the breach-of-contract claim was sufficient to preclude the summary judgment on the breach-of-contract claim. See Ex parte General Motors Corp., 769 So.2d 903, 909 (Ala.1999). This Court expressly pretermitted discussion of Pearson's and Prince's remaining issues challenging the merits of the summary judgment entered on Poole's breach-of-contract claim, including their challenge based on formation of the contract, which directly relates to whether a valid and binding contract existed between the parties. Prince I, supra.

In its order on remand entering a summary judgment for Pearson and Prince, the trial court concluded that Poole failed to present substantial evidence showing that an enforceable contract existed. Because this Court did not definitively address in Prince I the issue whether a binding contract existed between the parties, the law-of-the-case doctrine does not preclude the trial court's determination of that issue on remand. Accordingly, we conclude that the trial court was entitled to consider the issue whether a binding and enforceable contract existed between the parties.

2. Indefiniteness of Contract Terms

We now must determine whether the parties' February 15 letter is void because of the indefiniteness of its terms. The trial court relied on White Sands Group, L.L.C., supra, in its order entering a summary judgment in favor of Pearson and Prince, finding that Poole had failed to present substantial evidence showing that an enforceable contract existed, because, it reasoned, the terms of the February 15 letter were indefinite. This Court has stated:

White Sands, 998 So.2d at 1051. Additionally, in order for an alleged contract to be considered void based on the indefiniteness of its terms, the "`"[i]ndefiniteness must reach the point where construction becomes futile."'" Ex parte Conaway, 767 So.2d 1117, 1119 (Ala.2000) (quoting Conaway v. Nickles, 767 So.2d 1116, 1117 (Ala. Civ.App.1998) (Crawley, J., dissenting), quoting in turn Heyman Cohen & Sons, Inc. v. M. Lurie Woolen Co., 232 N.Y. 112, 114, 133 N.E. 370, 371 (1921)). "A court will, if possible, interpret doubtful agreements by attaching a sufficiently definite meaning to a bargain if the parties evidently intended to enter into a binding contract." 1 Richard A. Lord, Williston on Contracts § 4:21 (4th ed.2007). See also Parr v. Godwin, 463 So.2d 129, 132 (Ala.1984)(holding that "the ambiguity created by the incompleteness is subject to clarification and being made certain by parole evidence" where there was obvious intent to enter into a contract).

In White Sands, a developer, White Sands, sought to purchase from Tommy Langan certain lots located in a development known as Pilot Town. Langan owned the property on which Pilot Town was to be developed. White Sands addressed the following letter to Langan:

998 So.2d at 1045-46. Upon receipt, Langan penciled in some changes in the third paragraph and struck out the words "with waterfall" in the fourth paragraph. The letter was signed by White Sands' representative as the purchaser and initialed by Langan as the seller.

Subsequently, a third party, PRS II, submitted to Langan a proposal to purchase all the lots in Pilot Town, including the five lots purportedly contracted to White Sands. The proposal by PRS II came with the stipulation that Langan void the "unenforceable contract to White Sands" and that no lots would be carved out of Pilot Town and sold to other parties. Langan then returned White Sands' check for $10,000 representing White Sands' deposit, and informed White Sands that he had decided not to pursue a subdivision for Pilot Town. Thereafter, PRS II received a warranty deed for Pilot Town from Langan that included the lots White Sands had sought to purchase.

PRS II sued White Sands seeking a judgment quieting title to Pilot Town in PRS II and declaring that White Sands had no interest in Pilot Town. White Sands counterclaimed, asserting various claims against various entities, including a breach-of-contract claim against Langan. The trial court entered a summary judgment against White Sands on its breach-of-contract claim and in favor of PRS II on its quiet-title action.

On appeal, this Court identified the dispositive issue, as framed by the parties, as whether White Sands' letter to Langan regarding the purchase of the lots located in Pilot Town constituted an enforceable contract. In determining that the letter was not an enforceable contract and affirming the summary judgment on the breach-of-contract claim and the quiet-title action, this Court stated:

White Sands, 998 So.2d at 1051-53.

As discussed in detail above, Pearson and Prince argued in Prince I that the February 15 letter was not intended to be a complete integration of the parties' agreement. This Court noted that the February 15 letter accomplished only a partial integration of the parties' agreement because it reduced to writing the parties' agreement as to the only four issues it addressed: (1) fee-split percentages for the Moundville gasoline litigation, (2) funding for the costs associated with prosecuting the Moundville gasoline litigation, (3) division of the potential fees and expenses from the "Gordo Aquifer Class Action," and (4) those cases that explicitly were not subject to the "Fee Splits" and "Funding for Costs" provisions of the February 15 letter. 935 So.2d at 445. As argued by Pearson and Prince, this Court noted that the February 15 letter, by its express terms, failed to place an obligation on anyone to prosecute the Moundville gasoline litigation. Pearson and Prince argued, and this Court agreed, that the terms of the parties' respective obligations to prosecute the Moundville gasoline litigation were omitted from the February 15 letter and that Pearson and Prince were entitled to introduce parole evidence as to those terms. Prince I, 935 So.2d at 445-46. In determining that Pearson and Prince were entitled to introduce parol evidence as to the parties' obligations to prosecute the Moundville gasoline litigation, this Court stated:

Prince I, 935 So.2d at 444-46.

As noted in Prince I, Pearson testified in his deposition that Poole agreed to assist in working on the Moundville gasoline litigation and to work to end the dissolution dispute with Prince's former firm. Prince testified in his affidavit that "Poole was expected to refer new cases relating to the Moundville gasoline spill, assist with state agencies, and be available to assist with jury selection and at trial" of the Moundville gasoline litigation cases. Poole disputed Pearson's and Prince's contention that he had assumed obligations other than "to include in the pooled cases any Moundville gasoline cases that came his way."

On remand, Pearson presented parol evidence in the form of his affidavit, in which he testified:

Poole also presented parol evidence by way of his affidavit, in which he testified:

We find the facts of White Sands to be distinguishable from the facts in this case. In this case the evidence clearly indicates that the parties intended to enter into a contract with regard to the Moundville gasoline litigation and that the February 15 letter memorialized part of that agreement. Although the February 15 letter is silent as to the parties' obligations with regard to prosecuting the Moundville gasoline litigation, Pearson and Prince have contended, and the evidence indicates, that the parties had reached an oral agreement as to the terms of the parties' obligations to prosecute the Moundville gasoline litigation. Because the parties have indicated an intention to contract, parol evidence is admissible to clarify the omitted terms. Parr, supra. Although the parties have presented disputed evidence as to what the actual terms regarding their obligations to prosecute the Moundville gasoline litigation are, that dispute does not render the terms of the February 15 letter so indefinite "that construction becomes futile." Ex parte Conaway, 767 So.2d at 1119. Rather, it simply creates a question of fact for a jury to determine.

Further, unlike the parties in White Sands, it does not appear from the evidence that the parties left essential terms "open for future agreement." White Sands, 998 So.2d at 1052. The evidence indicates that here the parties did not leave open for future agreement the parties' obligations with regard to prosecuting the Moundville gasoline litigation; they simply disagree as to the terms of those obligations. Additionally, unlike the circumstances in White Sands, there is no evidence indicating that the February 15 letter or any other agreement of the parties left Poole with the "unbridled right to determine the nature of his performance." It appears from the evidence that Poole had certain obligations with regard to the Moundville gasoline litigation; however, the parties are in dispute as to the terms of those obligations.

Accordingly, we conclude that the terms of the parties' agreement as to Poole's obligations regarding the Moundville gasoline litigation are not so indefinite as to render the parties' agreement void and unenforceable. The trial court erred in entering a summary judgment in favor of Pearson and Prince on Poole's breach-of-contract claim based on indefiniteness of the contract terms.

3. Rule 1.5(e), Alabama Rules Professional Conduct

Poole next argues that the trial court erred in finding the parties' agreement unenforceable based on an alleged violation of Rule 1.5(e), Ala. R. Prof. Cond. Rule 1.5(e) addresses the division of a fee between lawyers who are not in the same firm. The rule provides:

The Scope to the Rules of Professional Conduct states, in part:

(Emphasis added.) The power to declare a contract void based on a violation of public policy "`is a very delicate and undefined power and, like the power to declare a statute unconstitutional, should be exercised only in cases free from doubt.'" Milton Constr. Co. v. State Highway Dep't, 568 So.2d 784, 788 (Ala.1990) (quoting 17 Am Jur.2d Contracts § 178 (1964)). "`The courts are averse to holding contracts unenforceable on the ground of public policy unless their illegality is clear and certain.... [T]he courts will not declare an agreement void on the ground of public policy unless it clearly appears to be in violation of the public policy of the state.'" Id. (emphasis omitted).

In Terry Cove North, Inc. v. Marr & Friedlander, P.C., 521 So.2d 22 (Ala.1988), the plaintiffs sued a law firm and its two attorneys, alleging, among other things, breaches of certain Disciplinary Rules (the predecessor to the Alabama Rules of Professional Conduct). The trial court entered a summary judgment in favor of the defendant attorneys on the counts premised on the alleged breach of the Disciplinary Rules. In affirming the summary judgment, this Court stated:

521 So.2d at 23. See also Ex parte Toler, 710 So.2d 415 (Ala.1998)(holding that a violation of the Rules of Professional Conduct may not be used as evidence and citing Terry Cove North for the proposition that the sole remedy for a violation of the Rules of Professional Conduct was the imposition of disciplinary measures); Gaylard v. Homemakers of Montgomery, Inc., 675 So.2d 363, 367 (Ala.1996) (holding that the "Rules of Professional Conduct are `self-imposed internal regulations' and do not play a role in determining the admissibility of evidence" and citing Terry Cove North for the proposition that the sole remedy for a violation of the Rules of Professional Conduct was the imposition of disciplinary measures); Baker v. Baker, 862 So.2d 659, 663 (Ala.Civ.App.2003) (holding that a breach of the Rules of Professional Conduct would not justify setting aside a divorce judgment and citing Terry Cove North for the proposition that the sole remedy for a violation of the Rules of Professional Conduct was the imposition of disciplinary measures), and B.W.T. v. Haynes & Haynes, P.C., 20 So.3d 815 (Ala.Civ.App.2009)(recognizing that the legislature has committed to the State Bar the sole authority to enforce Rule 1.5, Ala. R. Prof. Cond. and holding that the trial court lacked subject-matter jurisdiction in a declaratory-judgment action seeking a declaration as to the validity and enforceability of a contingency-fee agreement where the State Bar was not made a party to the action).

We conclude that the trial court erred to the extent that it determined the parties' agreement to be unenforceable as violative of Rule 1.5(e), Ala. R. Prof. Cond. As discussed in the Scope of the Alabama Rules of Professional Conduct and in the above-cited authorities, the sole remedy for a violation of Rule 1.5(e) is disciplinary in nature; therefore, the trial court lacked the authority to declare the parties' agreement unenforceable as violative of Rule 1.5(e).

Conclusion

The trial court erred in holding that the parties' agreement reflected in the February 15 letter was void because the terms were indefinite and that the parties' fee arrangement violated Rule 1.5(e), Ala. R. Prof. Cond. The summary judgment in favor of Pearson and Prince on Poole's breach-of-contract claim is reversed, and the cause is remanded for proceedings consistent with this opinion.

REVERSED AND REMANDED.

LYONS, WOODALL, SMITH, PARKER, and SHAW, JJ., concur.

COBB, C.J., recuses herself.