concurring.
¶ 1 The court answers today that Oklahoma’s right-to-work amendment need not be subjected to severability analysis. I write separately to (1) explain the purpose and application of severability analysis and (2) emphasize that each provision of Oklahoma’s right-to-work amendment remains valid, operating harmoniously with applicable federal law to form the expansive body of legal norms that govern labor-management relations within the State of Oklahoma.
¶2 Federal labor law, where applicable, and the Oklahoma right-to-work amendment 1 must operate in concert. Labor-management relations encompass three distinct groups for employment classification: (1) employment relationships regulated entirely by federal law,2 (2) employment contracts that fall within the narrow exception reserved for state governance by the Labor Management Relations Act (hereinafter “LMRA”),3 and (3) employment relationships outside the impact of federal law which are regulated exclusively by state lato.4 We must assume as a given *842that Oklahoma’s constitutional amendment evinces not only this state’s regulatory policy vis-a-vis the LMRA, 29 U.S.C. § 164(b), where applicable, but also voices the state’s policy for the labor market utterly unaffected by federal law.5 Drafters of the Oklahoma right-to-work amendment doubtless sought to regulate the window opened by the LMRA as well as the federally unregulated field of labor-management relations within this state. A contrary assumption would be unsupported by the express language of the amendment.
I.
WE ASSUME THE U.S. DISTRICT COURT CORRECTLY LIMITED APPLICATION OF OKLAHOMA’S RIGHT-TO-WORK AMENDMENT IN ACCORDANCE WITH EXTANT FEDERAL LAW
¶ 3 This court’s authority when responding to a certified question is limited to answering state-law questions when it is satisfied there “is no controlling decision of the Supreme Court or Court of Criminal Appeals, constitutional provision, or statute of this state.”6 Because severability is a matter of state law, the United States Court of Appeals for the Tenth Circuit deferred on the issue to this court’s answer about whether, on review of the U.S. Districts Court’s decision now on appeal, severability analysis with regard to Oklahoma’s right-to-work amendment may be entirely dispensed with as unnecessary.7
¶ 4 The Supremacy Clause of Article YI of the United States Constitution arms Congress with the power to preempt state law.8 Congress has regulated labor-management relations, allowing states to intrude solely upon a narrowly defined portion. Whether Oklahoma’s amendment fits within the narrow exception granted by Congress or reaches beyond and is hence preempted by federal law is exclusively a federal-law issue.9 This *843court doesn’t give a federal court advice on issues of federal law. Under the certified question statute, 20 O.S.2001 § 1602, we may give a federal court our answer solely on the issues of state law. For our answer today we must assume the preemptive impact to be that which stands decreed by the U.S. Court of Appeals for the Tenth Circuit.
II.
THE PURPOSE OF SEVERABILITY ANALYSIS
¶ 5 Severability analysis is a necessary undertaking when some, but not all, provisions of an enactment are deemed unconstitutional and hence must be voided. Its purpose is to determine whether non-offending statutory provisions may survive after the rejected invalid clauses are separated from the whole. The severability of a state constitutional or statutory enactment, which is a question of state law,10 is not contingent on the presence of an express severability clause within the particular enactment.11 Considerations relevant to severability analysis are outlined in the provisions of 75 O.S.2001 § 11a.12
¶ 6 Survival of remaining statutory provisions is appropriate when the valid and voided (as unconstitutional) provisions are not so “inseparably connected with and so dependent upon” each other that the surviving provisions would not have otherwise been enacted.13 Consideration must be given to whether the surviving provisions rely on the severed portion for meaning or enforcement.14 The terms of 75 O.S.2001 § 11a set forth a clear prerequisite for the employment of severability analysis. This may occur when a statutory provision or application of the statute is declared unconstitutional and is hence voided. If no provision is invalidated as unconstitutional, severability analysis is unnecessary and inappropriate.
*844III.
BECAUSE ALL PROVISIONS OF THE RIGHT-TO-WORK AMENDMENT REMAIN VALID, SEVERABILITY ANALYSIS IS RENDERED UNNECESSARY
¶ 7 As the court recognizes in its pronouncement and I discuss below, the judgment of the United States District Court for the Eastern District of Oklahoma, restricts the application of Oklahoma’s right-to-work amendment without rendering any of its provisions void as unconstitutional. The district court determined (1) employees subject to regulation under the RLA,15 the CSRA,16 the PRA17 and federal enclave jurisdiction are outside the scope of Oklahoma’s right-to-work amendment,18 (2) Article 23 § 1A subsection (B)(5), Okl. Const., exceeds the scope of authority granted the states by § 164(b) of the LMRA,19 and (3) Article 23 § 1A subsection (C) is outside the scope of authority granted by § 164(b) of the LMRA.20 After determining that limited aspects of the right-to-work amendment “conflict with and are preempted by the LMRA,”21 the district court turned its attention to the severability issue, but did not declare any right-to-work provision void as unconstitutional.
¶ 8 The judgment of the United States District Court for the Eastern District of Oklahoma pronounced that Article 23 § 1A subsections (B)(5) and (C) were “preempted by federal law as being outside the grant of authority conferred by Section 164(b) of the LMRA.”22 It does not follow from this conclusion that the provisions are void based on the determination that statutory provisions are preempted for exceeding the scope of federally granted authority.23 Rather, the district-court determination operates to condition or restrict the application of the provision instead of rendering it void.
¶ 9 The district court noted restrictions in the application of the right-to-work amendment that prevent the statute from conflicting with or exceeding the scope of authority granted by federal law. Applying the federal-law preemptions outlined by the district court, the right-to-work amendment is limited in its application by the following conditions (1) the amendment applies only to employees encompassed by the LMBR, (2) hiring halls that discriminate between members and non-members are prohibited, and (3) employee authorization is required before union dues may be deducted, the au*845thorization to remain irrevocable for one year.
¶ 10 The district court’s conclusion that Oklahoma’s right-to-work amendment applies only to employment relationships falling within the scope of § 164(b) of the LMRA articulates the restricted scope of the amendment. As the district court states, “application of the State of Oklahoma’s prohibition against union security devices is necessarily limited to those employees falling under the purview of the LMRA.”24 The practical effect of the district court’s declarations is to restrict the full range of right-to-work amendment provisions to those private labor-management relationships which do not substantially affect interstate commerce.
¶ 11 When addressing restrictions in subsections (B)(5) and (C) of the right-to-work amendment, the district court relied on federal law.25 The drafters of the right-to-work amendment sought primarily to regulate (1) those labor-management relations that lie within the narrow window of state regulation authorized by § 164(b) of the LMRA, and (2) labor-management relations completely outside the scope of federal authority. Labor relationships falling within the limited scope of state regulation allowed by § 164(b) stand limited by applicable federal law. That law dictates that these labor relationships permit non-discriminatory union hiring halls26 and an annual obligation once an employee authorizes a payroll deduction for union dues.27 Labor relationships within the exclusive authority of state governance are utterly unaffected by federal regulations. This leaves Oklahoma’s amendment fully applicable in those contexts.
¶ 12 Despite imposing federal-law restrictions on the right-to work-amendment, the district court refused to adopt a statutory construction that would defeat the constitutionality of Oklahoma’s amendment. Specifically, the district court applied the rules of statutory construction supporting “a construction of the state law which will uphold its validity as opposed to one which will render it void by reason of federal preemption.” 28 In adopting rules of statutory construction that uphold the overall validity of the right-to-work amendment, the district court acknowledged (1) “Oklahoma’s prohibition against union security devices is necessarily limited to those employees who fall under the purview of the LMRA,”29 and (2) Oklahoma’s right-to-work law does not include individuals governed by the “RLA, the CSRA, the PRA and federal enclave jurisprudence.”30 Preemption (by invalidation) of the right-to-work amendment was avoided through a statutory construction which restricts application of the amendment to the private labor sector and the area encompassed exclusively by the states.
¶ 13 The drafters of Oklahoma’s right-to-work amendment reasonably .contemplated and expected the limiting effect of applicable federal law. This is evidenced by the absence of an express or implied intention to avoid conforming or tailoring the text to applicable federal law. Recognizing that federal law does not operate on the universe of labor-management relations, the drafters sought to regulate (1) the narrow area of labor relations governed exclusively by the states, and (2) the federally authorized window opened by LMRA § 164(b). Because federal labor law is neither stagnant nor *846mummified in its present form, the drafters understood the outer boundaries of right-to-work amendment must be flexible to remain in conformity with present as well as future federal re-definitions. The restrictions imposed by the district court’s pronouncement clearly articulate specific limitations on Oklahoma’s right-to-work amendment while allowing the entire text of the amendment to stand available for application in conformity with extant federal law.
¶ 14 The district court’s judgment that federal law preempts the text of Article 23 § 1A subsections (B)(5) and (C) does not create a lacuna in the amendment. A facial four-corners’ examination of the amendment discloses complete survival of the legislation despite federal-law-imposed conditions being placed on the application of the right-to-work amendment. The impact of preemption on the amendment does not leave any unfilled territory that lies within the coverage of the statute, which if present, would call for sev-erability analysis. As no provisions of the right-to-work amendment are constitutionally invalidated by the district court’s declaratory judgment, the statutorily defined prerequisite for an employment of severability analysis (that a provision be declared void as unconstitutional) has not been met. The use of that analysis is hence inappropriate.
. Art. 23 § 1A, Okl. Const, (adopted by vote 25 September 2001).
. From the terms of the United States Constitution, Art. 1, § 8, cl. 3, the so-called Commerce Clause, Congress has drawn the authority to regulate any labor dispute affecting interstate commerce. See United Auto., Aircraft and Agric. Implement Workers of America v. Wisconsin Employment Relations Bd., 351 U.S. 266, 271, 76 S.Ct. 794, 797 100 L.Ed. 1162 (1956); Guss v. Utah Labor Relations Bd., 353 U.S. 1, 3, 77 S.Ct. 598, 599, 1 L.Ed.2d 601 (1957); N.L.R.B. v. Fainblatt, 306 U.S. 601, 606-07, 59 S.Ct. 668, 672, 83 L.Ed. 1014 (1939).
. The enactment of the Labor Management Relations Act of 1947 (commonly referred to as the Taft-Hartley Act), as an amendment to the National Labor Relations Act (NLRA), illustrates the expansive control Congress exercises in the area of labor relations. The LMRA is intended to achieve the following purpose:
in order to promote the full flow of commerce, to prescribe the legitimate rights of both employees and employers in their relations affecting commerce, to provide orderly and peaceful procedures for preventing the interference by either with the legitimate rights of the other, to protect the rights of individual employees in their relations with labor organizations whose activities affect commerce, to define and proscribe practices on the part of labor management which affect commerce and are mimical to the general welfare, and to protect the rights of the public in connection with labor disputes affecting commerce.
29 U.S.C. § 141(b).
The LMRA leaves a narrow window in which state regulation is permissible. See Garner v. Teamsters, Chauffeurs and Helpers Local Union No. 776 (A.F.L.), 346 U.S. 485, 488, 74 S.Ct. 161, 164, 98 L.Ed. 228 (1953); Pierce v. Otis Elevator Co., 1958 OK 254, ¶ 7, 331 P.2d 481, 483-84; McNish v. American Brass Co., 139 Conn. 44, 89 A.2d 566, 568-69 (1952), cert. denied, 344 U.S. 913, 73 S.Ct. 336, 97 L.Ed. 704 (1953) (Congress sought exclusively to govern only certain aspects of employment relationships by enacting the NRLA of 1935). Both the express terms and legislative history of 29 U.S.C. § 164(b) allow states to prohibit compulsory union membership as a condition of employment. N.L.R.B. v. Houston Chapter, Assoc. Gen. Contractors of America, Inc., 349 F.2d 449, 453 (5th Cir.1965), cert. denied, 382 U.S. 1026, 86 S.Ct. 648, 15 L.Ed.2d 540 (1966). See also Gray v. Local 714, Int'l Union of Operating Eng'rs, 778 F.2d 1087, 1090 (5th Cir.1985).
.Federal regulatory power over a labor-management relationship is drawn from (1) the employer’s activities affecting interstate commerce or from (2) local activities which substantially affect or relate to interstate commerce. N.L.R.B. v. Fainblatt, supra note 2; N.L.R.B. v. Dixie Terminal Co., 210 F.2d 538 (6th Cir.1954), cert. denied, 347 U.S. 1015, 74 S.Ct. 871, 98 L.Ed. 1138. The LMRA "provides jurisdiction in the federal dis*842trict courts over suits for violation of contracts between an employer and a labor organization representing employees in an industry affecting commerce as defined in [the Act].” United Ass'n of Journeymen v. Local 334, 452 U.S. 615, 616, 101 S.Ct. 2546, 2547, 69 L.Ed.2d 280 (1981).
Defining the phrase "affecting interstate commerce" requires a combining of two distinct concepts, "commerce" and "affecting commerce.” The term "commerce" is defined as:
trade, traffic, commerce, transportation, or communication among the several States, or between the District of Columbia or any Territory of tire United States and any State or other Territory, or between any foreign country and any state, Territory, or the District of Columbia, or within the District of Columbia or any Territory, or between points in the same sate but through any other State or any Territory or the District of Columbia or any foreign country.
29 U.S.C. § 152.1(6)
The phrase "affecting commerce" is defined as:
in commerce, or burdening or obstructing commerce or the free flow of commerce, or having led or tending to lead to a labor dispute burdening or obstructing commerce or the free flow of commerce.
29 U.S.C. § 152.1(7).
.Oklahoma’s right-to-work amendment has more than a single mission. It is intended to govern two different types of employment relationships (1) those that fall within the narrow window authorized by the LMRA, and (2) those entirely unaffected by federal labor law.
. The terms of 20 O.S.2001 § 1602 state in pertinent part:
The Supreme Court ... may answer a question of law certified to it by a court of the United States ... if the answer.may be determinative of an issue in pending litigation in the certifying court and there is no controlling decision of the Supreme Court or Court of Criminal Appeals, constitutional provision, or statute of this state.
. Leavitt v. Jane L„ 518 U.S. 137, 139, 116 S.Ct. 2068, 2069, 135 L.Ed.2d 443 (1996).
. The preemption doctrine stems from the Supremacy Clause of the United States Constitution. It invalidates any state law which contradicts or interferes with an act of Congress. Allis-Chalmers Corp. v. Lueck, 471 U.S. 202, 208, 105 S.Ct.. 1904, 1909, 85 L.Ed.2d 206 (1985) (citing Gibbons v. Ogden, 22 U.S. 1, 6 L.Ed. 23, 9 Wheat. 1 (1824)); Florida Lime & Avocado Growers, Inc. v. Paul, 373 U.S. 132, 142-143, 83 S.Ct. 1210, 1217-1218, 10 L.Ed.2d 248 (1963). See also Smith Cogeneration Mgmt, Inc. v. The Corporation Comm’n, 1993 OK 147, ¶ 21, 863 P.2d 1227, 1239.
. Whether state law is preempted by federal law is governed by federal law. Allis-Chalmers Corp., supra note 8, at 208, 105 S.Ct. 1904.
The federal appellate court correctly separated in this case the preemption issue, which it retains, from the severability issue, which it certified to this court. The former, preemption, pres*843ents a federal-law question whereas the latter, severability, constitutes a state-law question. See Holloway v. UNUM Life Insurance Co. of America, 2003 OK 90, - P.3d -.
. Leavitt, supra note 7, at 139, 116 S.Ct. 2068. See also Panhandle Eastern Pipeline Co. v. State of Oklahoma ex. ret, Comm'rs of the Land Office, 83 F.3d 1219, 1229 (10⅛ Cir.1996) (citing Jane L. v. Bangerter, 61 F.3d 1493, 1497 (10th Cir.1995), cert, denied, 520 U.S. 1274, 117 S.Ct. 2453, 138 L.Ed.2d 211 (1997)).
. "Severability of the non-offending sections ... does not necessarily depend on the presence of the clause.” Ethics Comm’n of Oklahoma v. Cullison, 1993 OK 37, ¶ 25, 850 P.2d 1069, 1077. See also United States v. Jackson, 390 U.S. 570, 585, n. 27, 88 S.Ct. 1209, 1218, n. 27, 20 L.Ed.2d 138 (1968).
. The pertinent part of 75 O.S.2001 § 11a states:
In the construction of the statutes of this state, the following rules shall be observed:
1. For any act enacted on or after July 1, 1989, unless there is a provision in the act that the act or any portion thereof or the application of the act shall not be severable, the provisions of every act or application of the act shall be severable. If any provision or application of the act is found to be unconstitutional and void, the remaining provisions or applications of the act shall remain valid, unless the court finds:
a. the valid provisions or application of the act are so essentially and inseparably connected with, and so dependent upon, the void provisions that the court cannot presume the Legislature would have enacted the remaining valid provisions without the void one; or
b. the remaining valid provisions or applications of the act, standing alone, are incomplete and are incapable of being executed in accordance with the legislative intent.
. This court recognizes the "clear legislative intent” that severing valid provisions of a statute from the invalid is appropriate when the "remaining provisions are so inseparably connected with and so dependent upon the void provisions that it is apparent the legislature would not have enacted the remaining valid provisions without the void ones.” Panhandle Eastern Pipeline Co., supra note 10, at 1230 (citing Kinney v. Board of Comm’rs of Tulsa County, Okla., 1995 OK CIV APP 49, ¶ 11, 894 P.2d 444, 448). See also Ethics Comm’n of Oklahoma, supra note 11, at ¶ 25 (a presumption of severability arises under the provisions of 75 O.S.2001 § 11a unless "(1) the non-offending portions [are] so connected with and dependent upon the unconstitutional portion that we cannot presume the Legislature would have enacted the former without the latter, or (2) that the non-offending portions are incapable of standing alone"). A similar standard applies to severability analysis when a statute is approved by a vote of the people. Severability is appropriate so long as the valid provisions (1) can stand independent from the severed statutory provisions and (2) voters would have approved the surviving statute.
. Ethics Comm'n of Oklahoma, supra note 11, at ¶ 26.
. Railway Labor Act, 45 U.S.C. § 151 etseq.
. Civil Service Reform Act, 5 U.S.C. § 7101 et seq.
. Postal Reorganization Act, 39 U.S.C. § 1201 et seq.
. Local 514, Transport Workers Union of America v. Keating, 212 F.Supp.2d 1319, 1326 (E.D.Okla.2002).
. Local 514, Transport Workers Union of America, supra note 18, at 1327.
. Local 514, Transport Workers Union of America, supra note 18, at 1327.
. Local 514, Transport Workers Union of America, supra note 18, at 1328.
. Local 514, Transport Workers Union of America, supra note 18, at 1327.
. Preemption is a matter of Congressional intent and "occurs when federal law displaces a body of state law on the same subject.” Lewis v. Sac and Fox Tribe of Oklahoma Housing Authority, 1994 OK 20, ¶ 16, 896 P.2d 503, 510. "The purpose of Congress is the ultimate touchstone” for determining preemption based on the commerce clause of the United States Constitution. Malone v. White Motor Corp., 435 U.S. 497, 504, 98 S.Ct. 1185, 1190, 55 L.Ed.2d 443 (1978) (quoting Retail Clerks Int’l Ass’n, Local 1625, AFL-CIO v. Schermerhorn 375 U.S. 96, 103, 84 S.Ct. 219, 222, 11 L.Ed.2d 179 (1963)).
Preemption occurs in four distinct instances (1) by express statutory language, (2) by a pervasive regulatory scheme which infers the presence of congressional intent that the federal regulation did not need supplemental state-law provisions, (3) when an actual conflict between state and federal laws makes it impossible to comply with both, or (4) where the objectives and purposes of Congress are thwarted by state law. Lewis v. Sac and Fox Tribe, 1994 OK 20 at ¶ 16, n. 49, 896 P.2d at 511, n. 49 (citing Todd v. Frank's Tong Service, Inc., 1989 OK 121, ¶ 5, 784 P.2d 47, 49; Missouri-Kansas-Texas R. Co. v. State, 1985 OK 108, ¶ 41, 712 P.2d 40, 47). See also Smith Cogeneration Mgmt., Inc., supra note 8, at ¶ 21. When a statute is preempted it becomes inapplicable to the arena governed by federal law but is *845not rendered nugatory in tire remaining arena that is free from federal-law impact.
. Local 514, Transport Workers Union of America, supra note 18, at 1324.
. Local 514, Transport Workers Union of America, supra note 18, at 1326-27 (citing Local 357, Int’l. Broth. of Teamsters, Chauffeurs, Warehousemen, and Helpers of America v. N.L.R.B., 365 U.S. 667, 81 S.Ct. 835, 6 L.Ed.2d 11 (1961); Laborers Int’l Union of North America, Local 107 v. Kunco, Inc., 472 F.2d 456, 458-59 (8th Cir.1973); N.L.R.B. v. Tom Joyce Floors, Inc., 353 F.2d 768, 770-71 (9th Cir.1965); N.L.R.B. v. Houston Chapter Ass’d Gen'l Contractors, 349 F.2d 449, 451 (5th Cir.1965), cert. denied, 382 U.S. 1026, 86 S.Ct. 648, 15 L.Ed.2d 540 (1966)).
. Supra note 25.
. 29U.S.C. § 186(c)(4).
. Local 514, Transport Workers Union of America, supra note 18, at 1325 (citing In re Bissell, 255 B.R. 402, 418 (Bankr.E.D.Va.2000)).
. Local 514, Transport Workers Union of America, supra note 18, at 1324.
. Local 514, Transport Workers Union of America, supra note 18, at 1326.