¶ 51. {concurring). This case presents an important issue with far-reaching consequences. Wisconsin circuit courts have jurisdiction over thousands of divorces across the state. To ease contentious litigation and settle their expectations, parties to a divorce often enter into purportedly "unmodifiable" stipulations establishing a set level of child support.
*652¶ 52. The court of appeals certified this case to this court so that we could clarify whether stipulations establishing unmodifiable, limited-duration floors on child support are contrary to public policy. The responsibility of this court is to provide clear guidance on this important issue that affects courts and litigants on a daily basis. I do not join the majority out of concern that its purported answer to this question creates confusion rather than clarity.
I
¶ 53. I agree with many of the underpinnings of the majority opinion. The child's best interests are, and should be, the guidepost of a court's determination on whether to modify child support. Majority op., ¶ 19. Parties may stipulate to a limited-duration, unmodifiable child support floor, and such stipulations are not categorically contrary to public policy. Id., ¶ 35. Such a stipulation can help a family going through a difficult divorce by curbing disagreements and litigation among the spouses. See id., ¶¶ 35-36. Nevertheless, a court retains the discretion to modify a limited-duration unmodifiable floor on child support when the facts of an individual case warrant a modification. Id., ¶¶ 15, 24.
¶ 54. As I see it, the court's discretion to modify an otherwise unmodifiable child support floor can be explained as follows: As a result of the party's stipulation to make child support unmodifiable for a limited duration, a party under a child support order may be estopped from later seeking its modification. However, even if all the elements of the equitable defense of estoppel are met, a circuit court may within its discretion decline to apply the doctrine of estoppel. See id., ¶ 36 (citing Jalovec v. Jalovec, 2007 WI App 206, ¶ 11, *653305 Wis. 2d 467, 739 N.W.2d 834). Circuit courts should be trusted to wisely exercise their discretion under the facts of a particular case.
¶ 55. This is precisely the analysis undertaken by the circuit court in this case. The court found that the elements of estoppel were met, and then it exercised its discretion, estopping Michael from seeking a modification. I agree with the majority that the circuit court examined the relevant facts, applied a proper standard of law, and used a demonstrated rational process to reach a conclusion that a reasonable judge could reach. Id., ¶ 48. Accordingly, there was no erroneous exercise of discretion.
II
¶ 56. The majority's approach is not so straightforward. Rather, as explained by the dissent, the majority's analysis of this reoccurring situation leaves many unanswered questions in its wake.
¶ 57. First, the majority employs circular reasoning. It concludes that unmodifiable stipulations are not contrary to public policy because, when they are contrary to public policy, they can be modified. See id., ¶ 3.
¶ 58. Second, the majority's discussion of when an unmodifiable stipulation should be modified is difficult to understand. The majority asserts that a circuit court may "consider circumstances in existence when the stipulation is challenged that were unforeseen by the parties when they entered into the stipulation if those circumstances adversely affect the best interests of the child." Id., ¶ 37.
¶ 59. Although the majority's analysis appears to rest upon the above statement, it is difficult to evaluate that statement's import. It may be that the majority *654means nothing more than what I have set forth above. That is, estoppel is an equitable defense, and even when all of the elements of estoppel are met, the circuit court must exercise its discretion in deciding whether to apply it.
¶ 60. However, the majority can also be interpreted as creating a new or different legal standard— unforeseen circumstances. According to the majority, a party must demonstrate unforeseen circumstances before a circuit court can exercise its authority to modify the parties' stipulation.1
¶ 61. Is this "new" standard really nothing more than the existing "substantial change in circumstances" standard under Wis. Stat. § 767.59(lf)? See dissent, ¶ 83. Does the majority intend to create a new standard? Whatever it is doing, it should be clearly stated in order to provide clear guidance to litigants and courts.
¶ 62. In addition to uncertainty about whether the majority has created a new standard, further questions remain. If the majority does intend to create a new standard, how does this new standard, "unforeseen circumstances," fit with the "substantial change in circumstances" standard for modifying orders in the absence of a stipulation? See Wis. Stat. § 767.59(lf). Is "unforeseen circumstances" a higher or lower hurdle than "substantial change in circumstances"? The majority does not say.
*655¶ 63. I agree that the circuit court did not erroneously exercise its discretion when it denied Michael's motion to modify child support on account of equitable estoppel. However, because I am concerned that the majority confuses rather than clarifies the law, I respectfully concur.
If the majority has created a new standard, I fear that its effect will be to limit the circuit court's authority to safeguard the best interests of the child. If a party must establish unforeseen circumstances, then the majority has shifted the focus from the best interests of the child to whether the litigants actually foresaw the circumstances when they entered into the stipulation.