Plaintiff-Appellee Lisa T. Kennedy brought suit against Defendant-Appellant Clemence Lubar in Colorado state court, asserting state common law claims for “[tjortious [interference with [employment [Relations” and tortious interference with “[prospective [ejmployment [rjela-tions.” Compl. at 14, App. to Br. of Def.Appellant (“App.”) at 17. Kennedy was employed as a part-time pharmacist in Store 100 of the King Soopers chain of grocery stores, and Lubar was her pharmacy manager. Kennedy alleges that Lu-bar engaged in intentional, malicious and willful misconduct which allegedly caused her termination from Store 100 and her inability to obtain subsequent employment at other King Soopers stores.
Lubar removed the case to the United States District Court for the District of Colorado based on her assertion that Kennedy’s state law claims were pre-empted by § 301 of the Labor Management Relations Act (“LMRA”), 29 U.S.C. § 185(a), and that the federal district court therefore had original subject matter jurisdiction over Kennedy’s claims. Notice of Removal at ¶¶ 4 and 8, App. at 23-24. Thereafter, Lubar filed a motion to dismiss Kennedy’s state law claims, also on the basis of federal preemption under § 301. Mot. to Dismiss at ¶¶ 3 and 19, App. at 49 and 60.
Kennedy responded with a motion for remand, asserting that the federal district court lacked jurisdiction over her state law claims because they were not рre-empted by § 301. Mot. for Remand at 1 and 8, App. at 137 and 144. The district court agreed and remanded the case, stating as follows:
The defendant filed a notice of removal on November 22, 2000, asserting that the claims are pre-empted by the Labor Management Relations Act, 29 U.S.C. § 185. The plaintiff filed a motion for remand on November 28, 2000. Upon careful review of the allegations of the complaint, it is clear that these are tort claims against an individual and not against the employer for a violation of any collective bargaining agreement or under any federal law.
Order of Remand at 1, App. at 146.
Thereafter, Lubar simultaneously filed a Petition for Writ of Mandamus and a Notice of Appeal. A two-judge panel of this court denied Lubar’s Petition for Writ of Mandamus, holding that although this court had jurisdiction to review the district court’s remand, the appropriate vehicle for redress was a direct appeal. In re Clemence Lubar, No. 00-1504, Order at 2 (10th Cir. Jan. 18, 2001), App. at 173. On *1297 appeal, Lubar asks this court to vacate the district court’s Order of Remand, and to instruct the district court to dismiss Kennedy’s claims with prejudice on the basis of federal pre-emption under § 301. Br. of Def.-Appellant at 30. Although Lubar has made a very strong case for pre-emption, we must nonetheless dismiss the appeal because 28 U.S.C. § 1447(d) absolutely precludes us from reviewing the district court’s Order of Remand. 1
28 U.S.C. § 1447(d) states that, subject to certain exceptions not applicable here, “[a]n order remanding a case to the State court from which it was removed is not reviewable on appeal or otherwise .... ” This strong statutory limitation on appellate review applies, however, only to remands based on 28 U.S.C. § 1447(c).
Albertson’s, Inc. v. Carrigan,
In determining whether or not a district court remanded the case on the grounds provided in § 1447(c), “we must independently review the record to determine the actual grounds upon which the district court believed it was empowered to remand.”
Dalrymple,
Applying these standards to the current case, it is clear that the district court’s sole basis for ordering remand was its determination that it lacked subject matter jurisdiction over Kennedy’s state law claims. Although the district court did not expressly use the term “subject matter jurisdiction” in its Order of Remand, the only fair reading of that order is that the district court’s decision was based entirely on its determination that Kennedy’s state tort claims were not pre-empted by § 301, and that, as such, there was no basis for the сourt to exercise jurisdiction over her lawsuit. The district court specifically found that Kennedy’s claims against her supervisor, as an individual, ^did not allege “a violation of any collective bargaining agreement or under any federal law.” Order of Remand at 1, App. at 146 (em *1298 phasis added). Implicit in this finding is a determination that it lacked subject matter jurisdiction over Kennedy’s claims. Moreover, Kennedy’s motion for remand itself asserted that remand was required only because the federal court lacked subject matter jurisdiction where her state law claims were not pre-empted by § 301. 2
A complete and accurate reading of the Order of Remand and the record before us makes it perfectly clear that the district court’s order
clearly [did] not reflect the typical non-jurisdictional determination involving a discretionary remand of supplementary or pendent claims, venue, abstention, comity or the waiver of opportunity to challenge proсedurally irregular removal. Instead, the order[ ] address[ed] key issues directly related to whether the district court could have exercised subject matter jurisdiction over the case[ ]- the presence of a federal question on the face of the plaintiffs’ complaint[ ] and/or the presence of a federal question in the form of a colorable federal ... defense.
Dalrymple,
At oral argument, however, Lubar asserted that wp should not apply the prohibitions of § 1447(d) in this case, arguing that principles of “law of the case” and waiver preclude us from dismissing her appeal. We address each of Lubar’s contentions in turn.
Lubar’s first contention is that because the mandamus panel already addressed the discrete issue of appellate jurisdictiоn in this case, basic “law of the case” principles preclude us from revisiting it on appeal. Although we recognize that the mandamus panel already decided that we could exercise jurisdiction over Lubar’s appeal, this decision was based entirely on its erroneous finding that the district court’s remand order was not grounded in § 1447(c), 3 and we disagree with Lubar’s position that “law of the case” principles prevent us from revisiting the jurisdictional question.
“ ‘[T]he lаw of the case doctrine posits that when a court decides upon a rule of law, that decision should continue to govern the same issues in subsequent stages in the same case.’ ”
McIlravy v. Kerr-McGee Coal Corp.,
However, law of the case principles apply only to decisions on the actual merits.
Wilmerv. Board of Cty. Comm’rs,
In any event, law of the case principles are not absolute. “Although courts are often eager to avoid reconsideration of questions once decided in the same proceeding, it is clear that all federаl courts retain power to reconsider if they wish.” Wright & Miller § 4478, at 789. We have routinely recognized that the law of the case doctrine is “discretionary, not mandatory,” and that the rule “ ‘merely expresses the practice of courts generally to refuse to reopen what has been decided, not a limit on their power.’ ”
Stifel, Nicolaus & Co., v. Woolsey & Co.,
Applying these basic “law of the case” principles, and in light of thе *1300 strong legislative mandate absolutely precluding our review of remand orders issued on the grounds articulated in § 1447(c), we exercise our discretion to reexamine the mandamus panel’s prior jurisdictional determination and revisit the jurisdictional question. In doing so, we conclude that the mandamus panel’s finding was clearly erroneous, and that the only reasonable reading of the district court’s order is that it remanded the case solely because it found that Kennedy’s claims were not pre-empted and that, as such, there was no federal subject matter jurisdiction. We find absolutely no evidence in the record before us to support the mandamus panel’s conclusion that the remand was based on considerations other than subject matter jurisdiction. To the contrary, as indicated above, Kennedy’s motion for remand asserted only arguments based on the district court’s lack of federal subject matter jurisdiction, and no other ground for remand was asserted or considered below. 7 Indeed, the mandamus panel’s order itself does not provide any suggestion about what other grounds the district court may have had for its remand order, 8 and no such grounds appear anywhere in the record. The mandamus panel’s jurisdictional conclusion was clearly erroneous, and law of the case principles do not prevent us from dismissing this appeal. 9
*1301 Lubar’s second contention is that Kennedy affirmatively waived the issue of jurisdiction and consented to our review by expressly adopting the mandamus panel’s holding that the district court’s Order of Remand was appealable “under 28 U.S.C. § 1291.” Br. of Pl.-Appellee at 1. Again, we disagree with Lubar’s contention.
Although Lubar is correct that we ordinarily do not consider matters not affirmatively raised by the parties in their opening briefs,
State Farm Fire & Cas. Co. v. Mhoon,
As a federal court of appeals, we are a court of limited jurisdiction and
*1302
must refrain from exercising jurisdiction unless we are certain that such jurisdiction has been granted us by Congress.
See Adams v. Reliance Standard Life Ins. Co., 225
F.3d 1179, 1182 (10th Cir.2000) (“In light of the limited subject matter jurisdiction granted to the federal courts by Congress, wе have a duty to satisfy ourselves that jurisdiction is appropriate.”)
11
Likewise, we are absolutely prohibited from exercising jurisdiction where it is expressly forbidden by Congress.
See Basso v. Utah Pwr. & Lt. Co.,
Based on the foregoing, we hold that we lack jurisdiction to review the district court’s Order of Remand. 13 Accordingly, this appeal is DISMISSED.
Notes
. We note, however, that Lubar is free to raise her substantive pre-emption defense in Colorado state court, and can re-file her 12(b)(6) motion to dismiss in that forum.
See, e.g., Niehaus v. Greyhound Lines, Inc.,
. See Mot. for Remand at 1, App. at 137 (document entitled "MOTION FOR REMAND (Lack of Subject Matter Jurisdiction),” and asserting that the action was "wrongfully removed, as this federal court fully lacks subject matter jurisdiction to address any aspect of Plaintiff's state law claims”); id. at 8, App. at 144 (asserting that "Plaintiff did not file this case in federal court for the simple reason there is no federal court subject matter jurisdiction”).
. The mandamus panel's order denying states, in relevant part, as follows:
The grounds provided by § 1447(c) are a defect in the removal procedure or lack of jurisdiction, neither of which was the district court’s reason for its remand order in this case. Therefore, review is not barred [by § 1447(d) ].
In re Clemence Lubar, No. 00-1504, Order at 2 (10th Cir. Jan. 18, 2001), App. at 173 (emphasis added).
. The court in Dean actually uses the term “res judicata," but it is nonetheless clear it is in fact applying “law of the case” principles.
.
See also Kirshner v. Uniden Corp. of Am.,
.See also Wright & Miller § 4478, at 790 & n. 5 (“Most recent decisions suggest that the major grounds that justify reconsideration involve an intervening change of controlling law, the availаbility of new evidence, or the need to correct a clear error or prevent manifest injustice.”) (emphasis added).
.In her Petition for Writ of Mandamus, Lu-bar asserted that appellate review was proper in spite of § 1447(d) because the district court failed to use a " 'good faith' process” in making its remand determinations. Pet. for Writ of Mandamus at 7-8, App. at 157-58 (quoting
Archuleta,
In
Archuleta,
we specifically held that § 1447(d) precludes us from reviewing a remand order where that order was based on a district court's finding that it lacked subject matter jurisdiction over the case, "even where the district court may have employed erroneous principles in conсluding that remand [was] required.”
. See In re Clemence Lubar, No. 00-1504, Order (10th Cir. Jan. 18, 2001), App. at 172-73.
. Lubar suggests that we are pоwerless to reconsider the mandamus panel’s prior jurisdictional determinations because there is no broad-based "jurisdictional exception” to the law of the case doctrine. Without deciding whether or not Lubar is correct, or whether or not the cases cited actually preclude the possibility of a jurisdictional exception in all cases, we simply point out that we do not rely on any such exception in this case. We rely only on the "clearly erroneous” exception, and the well recognized principle that application of "law of the case” doctrine is always discretionary, not mandatory.
Relying on
Burlington Northern & Santa Fe Ry. Co. v. Burton,
.
See Steel Co. v. Citizens for a Better Env't,
.
See also Bender v. Williamsport Area Sch. Dist.,
.
See also Tahy v. United States,
No. 98-4167,
. At oral argument, Lubar argued that if we decide not to exercise jurisdiction over orders of remand in cases such as this, our review of district court pre-emption determinations will be limited to only those cases where (i) motions for remand are denied, (ii) a district court remands for reasons other than those articulated in § 1447(с), or (iii) the district court exercises jurisdiction and then subsequently dismisses a plaintiff's state law claims. Lubar is absolutely correct; our previous cases have reviewed pre-emption determinations
only
in those limited circumstances.
See, e.g., Steinbach v. Dillon Cos.,
