FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

LOCAL JOINT EXECUTIVE BOARD OF       
LAS VEGAS,
                       Petitioner,
                                          No. 07-73979
ARCHON CORPORATION,
                      Intervenor,         NLRB No.
                                          28-CA-13274
               v.
                                           OPINION
NATIONAL LABOR RELATIONS
BOARD,
                     Respondent.
                                     
        On Petition for Review of an Order of the
            National Labor Relations Board

                  Argued and Submitted
           June 25, 2008—Pasadena, California

                  Filed August 27, 2008

    Before: William C. Canby, Jr., Susan P. Graber, and
             Richard A. Paez, Circuit Judges.

                  Opinion by Judge Paez




                          11849
           LOCAL JOINT EXECUTIVE BD v. NLRB   11851


                     COUNSEL

Michael T. Anderson, Davis, Cowell & Bowe, LLP, San
Francisco, California, for the petitioner.
11852           LOCAL JOINT EXECUTIVE BD v. NLRB
Julie B. Broido and Gregory P. Lauro, National Labor Rela-
tions Board, Washington, D.C., for respondent.


                              OPINION

PAEZ, Circuit Judge:

   This is the second time that Petitioner Local Joint Execu-
tive Board of Las Vegas, Culinary Workers Union Local 226
and Bartenders Union Local 165 (“the Union”)1 petitions for
our review of a National Labor Relations Board (“NLRB” or
“the Board”) order dismissing its consolidated complaints
against Hacienda Resort Hotel and Casino and Sahara Hotel
and Casino (“the Employers”)2 for unilaterally terminating
dues-checkoff before bargaining to agreement or impasse.
The dispute centers on the Board’s application of the unilat-
eral change doctrine as recognized by NLRB v. Katz, 

(1962). Under this doctrine, absent a waiver, an employer
violates sections 8(a)(1) and 8(a)(5) of the National Labor
Relations Act (“NLRA” or “the Act”), 29 U.S.C. § 158(a)(1)
and (5), if it makes a unilateral change in a term or condition
of employment—so-called “mandatory subjects” of
bargaining—without first bargaining over the relevant term.
In our prior decision in this case, Local Joint Executive Bd.
of Las Vegas v. NLRB (LJEB I), 

(9th Cir. 2002),
we granted the Union’s petition, vacated the Board’s decision
and remanded to the Board with instructions because we
could not discern the Board’s rationale for excluding, in the
absence of union security, dues-checkoff from Katz’ unilateral
  1
    Petitioner Local Joint Executive Board of Las Vegas is a committee of
two local labor unions, Culinary Workers Union Local 226 and Bartenders
Union Local 165. Local 226 and Local 165 are affiliated with the Hotel
Employees and Restaurant Employees International Union (AFL CIO).
  2
    Archon Corporation is the Employers’ successor in interest. We
granted Archon Corporation’s motion to intervene pursuant to Fed. R.
Appellate P. 15(d).
                LOCAL JOINT EXECUTIVE BD v. NLRB                 11853
change doctrine. In particular, we found that if “[t]he checkoff
is merely a means of implementing union security [as in Beth-
lehem Steel] . . . such reasoning would not support the rule
that the Board applies in this case.” 

(internal quota-
tion marks omitted). We asked the Board to “articulate a rea-
soned explanation for the rule it adopted, or [to] adopt a
different rule and present a reasoned explanation to support
it.” 

   On remand, the Board reaffirmed its dismissal of the com-
plaint but, reversing field, did not rely on the bright-line rule
articulated in its original decision. See Hacienda Hotel Inc.,
Gaming Corp. (Hacienda II), ___ N.L.R.B. ___, 351 NLRB
No. 32, 

, at *1 (Sept. 29, 2007). Instead,
the Board interpreted the collective bargaining agreements
(“the Agreements”) and found, without resolving whether in
the absence of union security dues-checkoff should be
excluded from Katz’ unilateral change doctrine, that the
Union had explicitly waived any right of employees to claim
dues-checkoff after the Agreements expired. 

Accordingly, the Board dismissed the Union’s complaint.

   In its petition for review, the Union argues that the Board
side-stepped the issue posed in our remand, but we conclude
that the Board was responsive to our instruction to “adopt a
different rule.” LJEB 

. The Board’s decision
does not, however, properly apply the rule it adopted. Where
a unilateral change is defended on a claim of contractual right,
the alleged waiver must be—as the Board acknowledges on
appeal—“clear and unmistakable.” Metro. Edison Co. v.
NLRB, 

, 708 (1983). There is simply no clear and
unmistakable waiver here. We again grant the petition for
review, vacate, and remand.
                       3
  I.   Background
  3
   We restate in part the facts of this case from our prior opinion, see
LJEB 

.
11854            LOCAL JOINT EXECUTIVE BD v. NLRB
   The Employer and the Union had collective-bargaining
relationships for more than thirty years. The 1989-1994 col-
lective bargaining agreements (the “Agreements”) were
embodied in separate, but substantially identical documents.
Each agreement contained the following dues-checkoff provi-
sion:

      The Check-Off Agreement and system heretofore
      entered into and established by the Employer and the
      Union for the check-off of Union dues by voluntary
      authorization, as set forth in Exhibit 2, attached to
      and made part of this Agreement, shall be continued
      in effect for the term of this Agreement.

(emphasis added). Exhibit 2 attached to each agreement pro-
vided:

      Pursuant to the Union Security provision of the
      Agreement between [name of hotel] and [the Union],
      the Employer, during the term of the Agreement,
      agrees to deduct each month Union membership
      dues (excluding initiation fees, fines and assess-
      ments) from the pay of those employees who have
      authorized such deductions in writing as provided in
      this Check-Off Agreement. Such membership dues
      shall be limited to amounts levied by the Unions in
      accordance with their Constitutions and Bylaws.
      Deductions shall be made only for those employees
      who voluntarily submit to the hotel employing them
      a written authorization in accordance with the “Au-
      thorization for Check-Off of Dues” form set forth
      below. It is the Union’s responsibility to provide the
      employees with this form.

(emphasis added). The State of Nevada, where the Employers
are located, is a “right-to-work” state.4 As a result, under sec-
  4
   Nevada’s right-to-work law provides:
        [n]o person shall be denied the opportunity to obtain or retain
                LOCAL JOINT EXECUTIVE BD v. NLRB                    11855
tion 14(b) of the Labor Management Relations Act
(“LMRA”), 29 U.S.C.§ 164(b), the Agreements legally could
not, and therefore did not, include a union security provision
requiring union membership as a condition of employment.5
The Agreements instead provided that the union-security
clauses would become effective only if state law changed to
allow union security.

   The Agreements expired on May 31, 1994. The Employers
continued to abide by the dues-checkoff arrangement for more
than a year after this expiration date. In June 1995, however,
after notifying the Union, the Employers ceased giving effect
to the dues-checkoff provision in the expired Agreements and
thereafter redirected amounts, which previously had been
deducted and remitted to the Union, to their employees as part
of their regular wages.

   On October 26, 1995, the General Counsel for the Board
issued consolidated complaints alleging that the Employers’
unilateral termination of dues-checkoff, without bargaining to
impasse, constituted an unfair labor practice in violation of
sections 8(a)(1) and 8(a)(5) of the Act. The administrative law
judge (“ALJ”) dismissed the complaints. Relying on the lan-
guage of the dues-checkoff provision, which stated that dues-
checkoff would “continu[e] in effect for the term of this
agreement,” the ALJ concluded that “it is unnecessary to
examine the state of the law on checkoff clauses, whether in

    employment because of nonmembership in a labor organization,
    [n]or shall . . . any corporation, individual or association of any
    kind enter into any agreement, written or oral, which excludes
    any person from employment or continuation of employment
    because of nonmembership in a labor organization.
Nev. Rev. Stat. § 613.250.
   5
     Section 14(b) of the LMRA permits states and territories to enact what
are commonly known as “right-to-work” laws prohibiting “agreements
requiring membership in a labor organization as a condition of employ-
ment.” 29 U.S.C. § 164(b)
11856         LOCAL JOINT EXECUTIVE BD v. NLRB
right-to-work [s]tates or otherwise” because “[t]he most rea-
sonable interpretation . . . is that [dues-checkoff] would con-
tinue through the duration of the contract but would not
survive thereafter.”

   On review, the Board affirmed the dismissal, but adopted
a different rationale. Hacienda Hotel, Inc. Gaming Corp.
(Hacienda I), 

(2000). Instead of relying on
the language of the dues-checkoff provisions, the Board rea-
soned that the Employers’ unilateral termination of dues-
checkoff did not constitute an unfair labor practice under sec-
tions 8(a)(1) and 8(a)(5) of the Act because dues-checkoff
was not subject to the Katz prohibition against unilateral
change. 

The Board traced its rule excluding dues-
checkoff from the unilateral change doctrine to its decision in
Bethlehem Steel Co., 

, 1502 (1962),
enforced in pertinent part, Indus. Union of Marine & Ship-
building Workers v. NLRB, 

, 621 (3d Cir. 1963).

As evidence that the rule was “well-established,”
the Board cited numerous Board and court decisions citing the
holding of Bethlehem Steel for the proposition that an
employer’s checkoff obligation does not survive the contract
that created the obligation. 

Two members of the
Board dissented, criticizing the Board’s application of the
holding in Bethlehem Steel to cases in which the collective
bargaining agreement contained no union-security provision.

   The Union petitioned this court for review. On October 28,
2002, we granted review and vacated the Board’s order. LJEB

. We found that we could not discern the
Board’s rationale for excluding dues-checkoff from the unilat-
eral change doctrine in the absence of a union security provi-
sion because the “Board’s finding creates substantial
ambiguity in the rationale underlying Bethlehem Steel’s hold-
ing regarding dues-checkoff.” 

. We granted the peti-
tion for review, vacated the decision of the Board, and
remanded for the Board to articulate a reasoned explanation
                LOCAL JOINT EXECUTIVE BD v. NLRB                 11857
for the rule it adopted, or to adopt a different rule and present
a reasoned explanation to support it. 

   On remand, the parties filed position statements and four
years later, on September 29, 2007, the Board reaffirmed its
dismissal of the complaint but again changed course. Return-
ing to the approach first adopted by the ALJ, the Board found
that the dues-checkoff provisions in the collective-bargaining
agreements contained explicit language limiting the Employ-
ers’ dues-checkoff obligation to the duration of the Agree-
ments.

      Not only does the dues-checkoff provision state that
      it “shall be continued in effect for the term of this
      Agreement,” but also Exhibit 2, incorporated by ref-
      erence in the checkoff provision, explicitly states
      that the Respondents agree to deduct monthly union
      dues “during the term of the Agreement” [emphasis
      added].

Hacienda II, 

, at *3. The Board determined
that, “[w]here, as here, the dues-checkoff provision itself con-
tains clear language linking dues-checkoff to the duration of
the collective-bargaining agreement, as opposed to general
durational language elsewhere[,] . . . the parties intended that
dues checkoff would not survive expiration of the agree-
ment.” 

Board did not directly address the
significance of any underlying statutory rights, the Board
apparently concluded that these contractual provisions estab-
lished that the Union had bargained away any statutory rights
it might have had with respect to dues-checkoff. As the Board
explained, the Union “explicitly waived any right to the con-
tinuation of dues checkoff as a term and condition of employ-
ment after expiration of the collective-bargaining agreement.”
Id.6 Again, two members of the Board dissented, objecting to
  6
   Although the Board’s decision used neither the words “clear and
unmistakable,” nor included citations to the relevant case law, we agree
with the Board’s counsel that the appropriate analysis is whether the
Union “clearly and unmistakably” waived its statutory protection against
post-expiration termination of dues-checkoff.
11858           LOCAL JOINT EXECUTIVE BD v. NLRB
the majority’s interpretation of the relevant contractual lan-
guage and arguing that a waiver of statutory protection
against unilateral changes in this context would “effectively
drain the Katz doctrine of any force.” 

   On October 10, 2007, the Union filed a petition for review.

  II.   Standard of Review

   The National Labor Relations Board “has the primary
responsibility for developing and applying national labor poli-
cy.” NLRB v. Curtin Matheson Scientific, Inc., 

,
786 (1990). Accordingly, we defer to its rules so long as “the
NLRB’s interpretation of the NLRA . . . is rational and con-
sistent with the statute.” United Food & Commercial Workers
Union, Local 1036 v. NLRB, 

, 766 (9th Cir.
2002) (en banc).

   With respect to collective bargaining agreements, however,
the Supreme Court has stressed that “the Board is neither the
sole nor the primary source of authority in such matters.” Lit-
ton Fin. Printing Div. v. NLRB, 

, 202 (1991); cf.
NLRB v. C & C Plywood Corp., 

, 428 (1967).
The Board has a limited role in interpreting contracts because
section 301 of the LMRA, 29 U.S.C. § 185, “authorizes fed-
eral courts to fashion a body of federal law for the enforce-
ment of . . . collective bargaining agreements.” 

(quoting Textile Workers Union of Am. v. Lin-
coln Mills of Ala., 

, 451 (1957)). Accordingly,
we review de novo the Board’s interpretation of the Agree-
ments. NLRB v. Dist. Council of Iron Workers of Cal. &
Vicinity, 

, 1098 (9th Cir. 1997).7
  7
    We need not address whether a different standard of review should
apply if the Board appropriately referred to extrinsic evidence when inter-
preting a collective bargaining agreement. Here, the Board based its con-
struction of the Agreements solely on the text of the relevant provisions.
                LOCAL JOINT EXECUTIVE BD v. NLRB                    11859
  III.    Analysis

   [1] Section 8(a)(5) of the NLRA makes it an unfair labor
practice for an employer to “refuse to bargain collectively
with the representatives of his employees.” 29 U.S.C.
§ 158(a)(5). Section 8(d) requires employers to bargain col-
lectively before introducing changes “with respect to wages,
hours, and other terms and conditions of employment.” 

An employer violates section 8(a)(5) by making any
unilateral changes to the mandatory bargaining subjects cov-
ered by section 8(d). See NLRB v. Wooster Div. of Borg-
Warner Corp., 

, 349 (1958).8

   [2] In Katz, the Supreme Court affirmed the Board’s deter-
mination that an employer violates sections 8(a)(5) and
8(a)(1) of the Act if it makes a unilateral change in a term or
condition of employment—so-called “mandatory subjects” of
bargaining—without first bargaining to impasse over the rele-
vant term. See, e.g., Litton, 

. Agreement or
impasse is required because the terms and conditions of
employment continue in effect by operation of the NLRA;
they are no longer agreed upon terms but terms imposed by
law, at least in so far as there is no unilateral right to change
them. See 

(stating that “the obligation not to
make unilateral changes is rooted not in the contract but in
preservation of existing terms and conditions of employ-
ment”) (internal quotation marks omitted).9 The Board has
  8
     A violation of section 8(a)(5) is also a violation of section 8(a)(1),
which makes it an unfair labor practice for an employer to “interfere with,
restrain, or coerce employees in the exercise” of their statutory right to
bargain collectively through representatives of their own choosing. 29
U.S.C. § 158(a)(1); see also Standard Oil Co. of Cal. v. NLRB, 

, 642 (9th Cir. 1968).
   9
     Most mandatory subjects of bargaining fall within the prohibition on
unilateral change. The Board has carved out exceptions to the unilateral
change rule including union-security and dues-checkoff provisions, and
arbitration and no-strike clauses, see 

. As we
held in LJEB I, however, the Board has not explained that why dues-
11860           LOCAL JOINT EXECUTIVE BD v. NLRB
recognized, however, that a union can contractually waive
statutory rights, including the right to bargain over changes in
fringe benefits. Gen. Tire & Rubber Co., 

,
592 (1985); Cauthorne Trucking, 

, 722
(1981). “Such waivers are valid because they ‘rest on the
premise of fair representation’ and presuppose that the selec-
tion of the bargaining representative ‘remains free.’ ” Metro.
Edison 

(quoting NLRB v. Magnavox Co.
of Tenn., 

, 325 (1974)).

   [3] The standard for waiving statutory rights, however, is
high. Proof of a contractual waiver is an affirmative defense
and it is the employer’s burden to show that the contractual
waiver is “ ‘explicitly stated, clear and unmistakable.’ ” Silver
State Disposal Serv. Inc., 

, 86 (1998) (quot-
ing Lear Siegler, Inc., 

, 447 (1989)); accord
Metro. 

(declining to “infer from a
general contractual provision that the parties intended to
waive a statutorily protected right unless the undertaking is
‘explicitly stated’ ”). Equivocal, ambiguous language in a bar-
gaining agreement, without more, is insufficient to demon-
strate waiver. See Tocco Div. of Park-Ohio Indus. Inc. v.
NLRB, 

, 626 (6th Cir. 1983).

   Waiver of a statutory right may be evidenced by bargaining
history, but the Board requires “the matter at issue to have
been fully discussed and consciously explored during negotia-
tions and the union to have consciously yielded or clearly and
unmistakably waived its interest in the matter.” Johnson-
Bateman Co., 

, 185 (1989). Because there

checkoff in the absence of union security should be excluded from the uni-
lateral change doctrine. LJEB 

. The Board expressly
declined to provide such an explanation in Hacienda II, but our holding
requires the Board to provide a reasoned basis for its rule excluding dues-
checkoff from the unilateral change doctrine in the absence of union
security. Should the Board seek to apply that rule following this remand,
our holding remains the law of this case.
                LOCAL JOINT EXECUTIVE BD v. NLRB                    11861
is no factual development of such a history here,10 the alleged
waiver is based wholly on the “explicit language limiting the
[Employers’] dues-checkoff obligation to the duration of the
agreements.” Hacienda II, 

, at *1.

   Therefore, as the Board recently emphasized in its decision
in Provena Hospitals, the Board has,

       in decisions too numerous to cite . . . applied the
       clear and unmistakable waiver analysis to all cases
       arising under Section 8(a)(5) where an employer has
       asserted that a [contractual] provision authorizes it to
       act unilaterally with respect to a particular term and
       condition of employment. . . .

       [t]he clear-and-unmistakable waiver standard . . .
       requires bargaining partners to unequivocally and
       specifically express their mutual intention to permit
       unilateral employer action with respect to a particu-
       lar employment term, notwithstanding the statutory
       duty to bargain that would otherwise apply.

Provena Hosps., ___ N.L.R.B. ___, 350 NLRB No. 64, 

at *4-5 (Aug. 16, 2007) (footnote omitted)
(emphasis added); see also C & C 

(approving of the Board’s adoption of the clear-and-
unmistakable standard). Although the Board has recently
engaged in an internal debate over whether to abandon this
standard, it has “specifically declined” to do so. Provena
Hosps., 

at *5.11 We turn to whether the
  10
      In American Distributing, we noted that such a waiver can occur “by
express contractual provisions, by bargaining history, or by a combination
of the two.” Am. Distrib. Co. v. NLRB, 

, 450 (9th Cir. 1983).
The Board has never suggested—nor has there been factual development
in the record—that there was relevant bargaining history, union inaction,
or that the parties had bargained to an impasse before the Employers ter-
minated dues-checkoff.
   11
      The competing standard is the so-called “contract coverage” standard,
which originated in the District of Columbia Circuit and has since been
11862            LOCAL JOINT EXECUTIVE BD v. NLRB
Board properly interpreted the Agreements when it found that
the Union clearly and unmistakably waived its statutory
rights.

  A.    “Clear and Unmistakable” Waiver

   The Board argues that because “the dues-checkoff provi-
sion itself contains clear language linking dues-checkoff to
the duration of the collective-bargaining agreements, as
opposed to general duration language elsewhere in the agree-
ment,” the Union explicitly bargained away its rights. We dis-
agree.

   [4] Although a general durational clause, without more,
does not defeat the unilateral change doctrine, Honeywell
Int’l, Inc. v. NLRB, 

, 131-32 (D.C. Cir. 2001),
such language within a specific contractual provision does not
necessarily establish that the Union bargained away its rights.
The Board’s precedent has plainly and consistently distin-
guished between language that states a particular provision
applies “during” the contract term, and language that states
the relevant benefit will “terminate” at the end of the contract
term. Only where the provision states that the benefit will
“terminate” has the Board found a clear and unmistakable
waiver.

   In Cauthorne Trucking, the intra-provision language
explicitly stated that all employer obligations under the pen-
sion agreement would “terminate” on expiration of the con-

.12 The Board determined that this

adopted by the Seventh and First Circuits. See Dep’t of Navy v. Fed. Labor
Relations Auth., 

(D.C. Cir. 1992); NLRB v. United States
Postal Serv., 

(D.C. Cir. 1993); Chi. Tribune Co. v. NLRB, 

(7th Cir. 1992); Bath Marine Draftsmen’s Ass’n v. NLRB, 

, 25 (1st Cir. 2007). We have not adopted the “contract coverage”
standard and neither party has suggested that we now do so.
   12
      The relevant provision stated, “It is understood and agreed that at the
expiration of any particular collective bargaining agreement by and
                 LOCAL JOINT EXECUTIVE BD v. NLRB                       11863
language expressed a clear intent to relieve the employer of
any obligation to make payments after contract expiration. 

argues that its position in this case is “consis-
tent” with Cauthorne Trucking because, even though the text
of the dues-checkoff clauses is not identical to that found in
Cauthorne Trucking, the parties’ intent is nonetheless simi-
larly clear.

   [5] This argument is not persuasive. First, as a matter of
plain interpretation, the contractual language that an obliga-
tion will “terminate” on expiration of an agreement is simply
not equivalent to contractual language that an obligation
“shall be continued” “during” the agreement. The latter says
nothing about what happens after the agreement expires. Sec-
ond, subsequent Board decisions explicitly reject such elision.
In a series of cases, the Board has distinguished Cauthorne
Trucking and established that a clear and unmistakable waiver
of the obligation to continue providing benefits requires
explicit contract language authorizing an employer to termi-
nate its obligations.

  In KBMS, Inc., the Board found that language requiring that
contributions be made “as long as a Producer is so obligated
pursuant to said collective bargaining agreements” did not
meet the standard under Cauthorne Trucking because this lan-
guage did not “deal with the termination of the employer’s
obligation to contribute to the funds.” 

, 849
(1986) (emphasis omitted and added).13 Similarly, in Schmidt-

between the Union and any Company’s obligation under this Pension
Trust Agreement shall terminate unless, in a new collective bargaining
agreement, such obligation shall be continued.” Cauthorne 

.
   13
      The Board’s attempt to distinguish KBMS on the basis that the same
trust article explicitly provided that it was not intended to alter the applica-
ble CBA is not persuasive, because the KBMS Board specifically found
that the text of the relevant provision “does not purport to deal with the
termination of the employer’s obligation to contribute to the 

(emphasis added).
11864           LOCAL JOINT EXECUTIVE BD v. NLRB
Tiago Constr. Co., 

, 366 (1987), the Board
found no contractual waiver and adopted the ALJ’s finding
that the case could be distinguished from Cauthorne Trucking
because the language requiring that employer contributions to
the pension fund be “in accordance with” a Pension Agree-
ment “does not on its face . . . specifically state that Respon-
dent’s obligation to contribute to the pension trust fund ends
with the expiration of the current collective-bargaining con-
tract.”14 See also 

n.7. In Natico, Inc., 

(1991), the Board again did not find a waiver on the basis
of language almost identical to the language in this case.
There, the provision stated that the parties agreed that the pen-
sion program “will remain in effect for the term of this
agreement.” 

(emphasis added). The Board adopted
the ALJ’s finding that “[t]he contractual language does not
state that the pension program will terminate on the expiration
of the contract. It appears that language to that effect is
required either in the collective-bargaining agreement or in
the underlying pension agreement to satisfy a waiver condi-
tion.” 

(emphasis added).

   [6] Further, the Board has refused to infer termination when
the provisions at issue have included language that extends
benefits for a specified period beyond the term or duration of
the contract. In NLRB v. General Tire and Rubber Co., 

, 588 (6th Cir. 1986) (per curiam) (enforcing Gen.

), the court affirmed the Board’s
position that where a provision allowed for “the benefits . . .
[to be] provided for ninety (90) days following termination,”
such language could not be understood as a clear and mistak-
able waiver with respect to the continuation of benefits
beyond the ninety-day period. The Board found that the rele-
  14
    The Board also attempts to distinguish Schmidt-Tiago as falling short
of a clear and unmistakable waiver on the basis that the relevant analysis
continued, “[m]oreover . . .” and listed additional reasons that the waiver
was not clear and unmistakable. The import of Schmidt-Tiago here, how-
ever, is how the durational language was treated.
              LOCAL JOINT EXECUTIVE BD v. NLRB             11865
vant provision “is silent on the matter of payment of benefits
following the ninety-day period.” 

In
other words, far from drawing the inference that after ninety
days the benefits would be terminated, the Board found that
the provision could stand only for the proposition that “the
company would provide an additional ninety days of coverage
beyond the expiration of the agreement.” Id.; see also Gen.

(“Nowhere in this contract provi-
sion is there mention of what is to occur to these supplemental
benefits after the 90 days have expired. In these circum-
stances, we find no clear and unmistakable waiver of the right
to bargain over these supplemental benefits after the 90-day
period.”).

   [7] In light of the text of the Agreements’ durational provi-
sions and the Board’s clear and consistent position on similar
provisions, the Board’s interpretation of the Agreements here
does not withstand de novo review. The dues-checkoff provi-
sions do not state that checkoff will terminate on expiration
of the Agreements, and the Board’s own precedent demon-
strates that it has refused to infer such termination—even
where those provisions purport to continue benefits only for
a limited period of time following the contract expiration. The
durational clauses here simply do not amount to a clear and
unmistakable waiver of the Union’s statutory rights.

  IV.   Conclusion

   The Union did not clearly and unmistakably waive its claim
to protection from unilateral change following the expiration
of the Agreements. We therefore grant the petition for review,
vacate the decision of the Board, and remand. Although there
is little doubt that the Board’s delay in issuing a decision in
this case is—as the Union vigorously charged—“deplorable,”
we do not agree that such a delay precludes a remand for fur-
ther proceedings. “It is well established that an agency’s
action must be upheld, if at all, on the basis articulated by the
agency itself.” Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. State
11866        LOCAL JOINT EXECUTIVE BD v. NLRB
Farm Mut. Auto. Ins. Co., 

, 50 (1983); see also
Allentown Mack Sales & Serv., Inc. v. NLRB, 

,
374 (1998) (citing SEC v. Chenery Corp., 

(1943)). Moreover, with the “clear and unmistakable” escape
hatch closed, the question squarely in front of the Board is
whether dues-checkoff in right-to-work states is subject to
unilateral change, or whether, under such circumstances,
dues-checkoff is a mandatory subject of bargaining. The
Board is the appropriate body for developing and applying
national labor policy and it should resolve such questions in
the first instance.

   We again instruct the Board to explain the rule it adopted
in Hacienda I, or abandon Hacienda I to adopt a different rule
and present a reasoned explanation to support it. The Union’s
petition for review is granted, the decision of the Board is
vacated, and the matter is remanded to the Board.

  PETITION GRANTED;         DECISION             VACATED;
REMANDED with instructions.