In this procedural motley, a band of plaintiffs — the eponymous BIW Deceived — locks horns with Local S6 of the Industrial Union of Marine and Shipbuilding Workers (the Union) over issues pertaining to removal and remand. The peculiarities of this engagement impel us to adumbrate our necessarily circuitous decisional path. After delineating the relevant facts and procedural history, we address whether the plaintiffs have waived their right to appeal either by inviting the judgment or by failing to seek our intervention at an earlier date. Finding no default, we proceed to the merits — a journey that requires us to touch upon doctrinal aspects of preemption under federal labor law and to explore a question of first impression concerning the exercise of federal question jurisdiction in the context of the artful pleading doctrine. At journey’s end, we conclude that the plaintiffs’ complaint presents a colorable federal question and that, therefore, the district court did not err when it refused to return the case to a state venue.
I. BACKGROUND
Because this action stumbled near, the starting gate, the record is stunted and the facts before us are sparse. We present them as best they present themselves.
In the fall of 1995, Bath Iron Works (Bath or BIW) hired a number of electricians and pipefitters., ..The Union participated in the job interviews pursuant to the terms of an existing collective bargaining agreement (the CBA). The plaintiffs allege that during these interviews the Union told them that they would “be employed at least until the expiration of the current Union contract [August 1997]” and “probably until the end of the decade;” that Bath “had more work for electricians and pipefitters than it could handle;” and that Bath “was hiring fewer electricians and pipefitters than it needed, so that the employees would be assured of continuing employment.” The plaintiffs further allege that they relied on these blandishments, accepted offers of employment, and left other jobs to move to Maine and work for Bath. But, the plaintiffs say, the Union bad led them down a primrose path; they were laid off early in 1996.
II. PROCEDURAL HISTORY
Angered by this fecklessness, the former employees, joined together to form “BIW Deceived” and sue the Union in a Maine state court. 1 Their complaint alleged negligence, fraudulent misrepresentation, fraud in the inducement, infliction of emotional distress, loss of consortium, intentional nondisclosure, and unjust enrichment. The Union promptly removed .the action to the federal district court. When the plaintiffs sought remand on the ground that their suit involved only state-law claims, the Union responded by asserting that all the plaintiffs’ claims were subject to preemption under the National Labor Relations Act (NLRA), 29 U.S.C. § 151 et seq., and/or the Labor Management Relations Act (LMRA), 29 U.S.C. § 185 et seq.
Judge Carter resolved the removal/remand dispute in the Union’s favor. He denied the plaintiffs’ motion, asserting in a two-page order that “the claims for relief set forth in the Complaint are all derivative, from and dependent for their resolution upon duties *828 defined and imposed by federal law, which law occupies the field and, by mandate of Congress, closes the field to state regulation.”
That order produced a strange reaction: the plaintiffs moved for entry of final judgment in the defendant’s favor. They reasoned that, in refusing to remand, the district court had “conelu[ded] that federal law preempts all state claims,” and that this conclusion “le[ftj nothing more to be litigated” in that court. Judge Carter denied this motion without elaboration.
Shortly thereafter, Magistrate Judge Cohen presided over a status conference during which the plaintiffs represented that they had “no interest in [pressing] any federal-law claims” and that they desired the entry of final judgment in order to “appeal the [district court’s] preemption ruling.” The Union agreed not to oppose the entry of judgment in its favor. The next day, the plaintiffs moved for reconsideration and for entry of final judgment, specifically “abandoning] any and all federal claims.” This time Judge Carter granted their motion and entered final judgment, without prejudice to the plaintiffs’ right to seek review. This appeal followed.
III. APPELLATE JURISDICTION
It is a federal court’s obligation to assure itself of the existence of subject matter jurisdiction even if no party presses the question.
See American Policyholders Ins. Co. v. Nyacol Prods., Inc.,
In several circuits a party who consents to the entry of judgment forfeits any right to appeal from that judgment.
See, e.g., Tel-Phonic Servs., Inc. v. TBS Int’l, Inc.,
This evidence clearly shows the plaintiffs’ unequivocal intention. Under
Coughlin,
then, we have discretion to accept the appeal insofar as it relates to a prior (contested) order notwithstanding the plaintiffs’ later consent to the entry of the final judgment itself.
See Coughlin,
Even so, our appellate jurisdiction is not free from doubt. The parties treat this appeal as if Judge Carter dismissed the suit because the various causes of action were preempted, but this is an inaccurate characterization of what actually transpired. There was no dismissal: while Judge Carter expressed his belief that the plaintiffs’ claims were preempted, the only ruling that he made on a contested matter consisted of denying the plaintiffs’ motion to remand. This ruling did not require a finding of preemption; it only required a finding that the Union had made a colorable showing of federal jurisdiction.
See infra
Part V. That
*829
the judge’s remarks swept more broadly does not alter the reality of events. It is settled beyond peradventure that a party can appeal only from an adverse order or judgment, not from a judge’s ruminations.
See Logue v. Dore,
The district court entered that order on July 3, 1996, and the plaintiffs did not file their notice of appeal until October 25, 1996. In some circuits, a disappointed suitor must appeal the denial of a motion to remand within the standard appeal period (here, thirty days,
see
Fed. R.App. P. 4(a)(1)), or else forever hold his peace.
See Marshall v. Manville Sales Corp.,
IV. THE LEGAL FRAMEWORK
There are three interlocking pieces to the applicable legal framework. We trace their contours.
A. Preemption.
In' the labor-law arena, preemption — the displacement of state law by the force of federal law — is a familiar phenomenon. Several different strains of preemption flourish in this field, each possessing somewhat different roots and each casting a uniquely configured shadow. Two of these preemption theories bear upon the instant ease.
1.
Section 301 of the LMRA, 29 U.S.C. §, 185, confers federal jurisdiction over “[s]uits for violation of contracts between an employer and a labor organization representing employees in an industry affecting commerce.” From this austere beginning, the Supreme Court determined that it had the authority to craft a federal common law that would effect section 301’s objectives.
See Textile Workers Union v. Lincoln Mills,
We recently visited this corner of the law in
Flibotte v. Pennsylvania Truck Lines,
Though section 301 is omnipotent within its sphere, it is not. endlessly expansive. The Court has warned that it “cannot be read broadly to pre-empt nonnegotiable rights conferred on individual employees as a matter of state law,”
Livadas v. Bradshaw,
2.
Preemption also can occur by operation of the so-called duty of fair representation (DFR). A union acting in its representative capacity owes this duty to those on whose behalf it acts.
See Ford Motor Co. v. Huffman,
A complaint that states a DFR claim “allege[s] a breach by the Union of a duty grounded in federal statutes and ... federal law. therefore governs [the] cause of action.”
Id.
Consequently, state law is preempted whenever a plaintiffs claim invokes rights derived from a union’s duty of fair representation.
See Condon v. Local 2944,
B. Standard of Review.
Although the parties gloss over the point, we emphasize that the only appealable order that the district court entered during the short life of this case is the order denying the plaintiffs’ motion to remand. The denial of a motion to remand a removed case to the state' court involves a question of federal subject matter jurisdiction and thus engenders de novo review.
See Rivet v. Regions Bank,
In this instance, the Union effected removal under 28 U.S.C. § 1441(b) (permitting the removal of civil actions over which United States District Courts have original federal question jurisdiction). Hence, our review must focus on “whether the federal district court would have had original jurisdiction of the case had it been filed in that court.”
Grubbs v. General Elec. Credit Corp.,
C. Federal Question Jurisdiction.
Federal district courts have original jurisdiction over “federal question” cases— that is, eases “arising under the Constitution, laws, or treaties of the United States.” 28 U.S.C. § 1331. The gates of federal question jurisdiction are customarily patrolled by a steely-eyed sentry — the “well-pleaded complaint rule” — which, in general, prohibits the exercise of federal question jurisdiction if no federal claim appears within the four corners of the complaint.
See International College of Surgeons,
-U.S. at-,
Whereas preemption by federal law is a defense-that ordinarily does not give rise to federal question jurisdiction,
see Caterpillar, Inc. v. Williams,
This powerful preemption principle propels a significant exception to the well-pleaded complaint rule — the artful pleading doctrine. The doctrine empowers . courts to look beneath the face of the complaint to divine the underlying nature, of. a claim, to determine whether the plaintiff has sought to defeat removal by asserting a federal claim under state-law colors, and to act accordingly.
See Federated Dep’t Stores, Inc. v. Moitie,
In this respect, we believe that DFR preemption operates in much the same fashion as section 301 preemption. While we have not heretofore inquired whether DFR preemption, like section 301 preemption, works an exception to the well-pleaded complaint rule, the answer seems obvious. Because federal law completely governs the duties owed by an exclusive -collective bargaining representative to those within the bargaining unit,
see Vaco,
Y. THE LITMUS TEST
The foregoing articulations of complete preemption, the standard of review, and the artful pleading doctrine are helpful, but they do not tell us how certain a court must be that an artfully pleaded complaint contains a federal question before denying a motion to remand. Although our research has not revealed any ready-made solution to this dilemma, we conclude that the artful pleading doctrine permits a district court to recharacterize a putative state-law claim as a federal claim when a review of the complaint, taken in context, reveals a colorable federal question within a field in which state law is completely preempted. We summarize the reasoning that undergirds this conclusion.
As a matter of common practice, a district court confronted with a question of subject matter jurisdiction reviews a plaintiffs complaint not to judge the merits, but to determine whether the court has the authority to proceed. When conducting this inquiry^ the court only asks whether the complaint, on its face, asserts a colorable federal claim.
See Aldinger v. Howard,
This formulation is reinforced by the principles articulated in
Merrell Dow Pharm., Inc. v. Thompson,
VI. THE MERITS
Having fashioned the standard by which we must gauge the propriety of removal and remand, we conclude without serious question that the instant complaint reveals a col-orable question of federal law and that, therefore, the district court did not err when it denied the motion to remand.
We start with the plaintiffs’
negligence
claim and its relationship to section 301 of the LMRA. This claim can survive
Razvson-hased
preemption under section 301 only if the Union acted “in a way that might violate the duty of reasonable care owed to every person in society.”
Rawson,
Even were we to assume for argument’s sake that the plaintiffs’ negligence claim, so recharacterized in light of section 301, does not raise a colorable federal claim, we still would be bound to affirm the district court’s denial of remand on the ground that the claim also is arguably preempted via the duty of fair representation. The fact that the plaintiffs were not members of the Union at. the time the statements were made does not command a contrary conclusion for a union owes a duty of fair representation to nonmembers whom it has undertaken constructively to represent.
See, e.g., Steele v. Louisville & Nashville R.R. Co.,
Let us be perfectly clear. Because of the nearly empty record, we cannot say with certitude whether we would find ultimately that federal preemption applies in the instant case. At this stage of the proceedings, however, we need not go that far; to uphold the district court’s exercise of federal question jurisdiction, we need only conclude that, despite the plaintiffs’ state-law stylings, the complaint, articulates at least one. colorable federal claim. Properly recharacterized, the plaintiffs’ complaint falls into this category.
To this point, we have trained our sights on the negligence claim. While we believe that, for the most part, the other claims contained in the plaintiffs’ complaint similarly state claims that, when recharacterized, are colorably federal in nature,. we need not probe the point too deeply. A federal court that exercises federal question jurisdiction over a single claim may also assert supplemental jurisdiction over all state-law claims that arise from the same nucleus of operative facts.
See
28 U.S.C. § 1367(a);
see also International College of Surgeons,
— U.S. at-,
VIL CONCLUSION
We need go no further. For the reasons stated herein, we conclude in the course of de novo review that the district court correctly exercised federal question jurisdiction when it denied the plaintiffs’ motion to remand. Consequently, the judgment to which the plaintiffs consented must stand.
Affirmed.
Notes
. Two of the plaintiffs are former employees' spouses. Since their claims for loss of consortium are derivative, we refer to the informal plaintiff class as if it were composed solely of ex-employees.
. The specific exceptions mentioned by the
Coughlin
court involve "a showing of either lack of actual consent, fraud in obtaining consent, lack of federal jurisdiction, or mistake.”
. Section 9(a) provides in pertinent part:
Representatives designated or selected for the purposes of collective bargaining by the majority of the employees ... shall be the exclusive representatives of all the employees ... for the purposes of collective bargaining in respect to rates of pay, wages, hours of employment, or other conditions of employment....
29 U.S.C. § 159(a).
.
Siler v. Louisville & Nashville R.R. Co.,
