This is an appeal from an order of the District Court for the Eastern District of Washington dismissing Appellant’s amended complaint for lack of subject matter jurisdiction. Appellant sought to have the District Court set aside a decision made by the National Labor Relations Board and to order the Board to conduct an election.

Appellant filed a petition with the Board pursuant to Section 9(c) of the National Labor Relations Act, as amended ( 61 Stat. 136 , 73 Stat. 519 , 29 U.S.C. § 151 et seq.), hereinafter called “the Act”, seeking to be certified as bargaining representative for some thirty-five truck drivers employed by the Boise Cascade Corporation. The Appellant urged the Board to find that a craft unit limited to truck drivers or truck drivers and mechanics was appropriate and that those employees should be severed from the existing plant unit comprising all of the employer’s production and maintenance employees currently represented by the Lumber and Sawmill Workers Union. The employer and incumbent union urged that the larger production and maintenance plant unit was appropriate and that the Board should refuse to sever the craft unit.

After a full hearing, the Board filed its written decision and order ( 148 NLRB No. 53 (1964)), holding that the truck drivers involved were functionally and administratively in the basic lumber industry and stated in part:

In the District Court, the Appellant contended that the Board’s adherence to the “Weyerhaeuser principle” constituted a clear violation of Section 9(b) (2) of the National Labor Relations Act, as amended in 1947, and violated the due process of law clause of the Fifth Amendment to the Constitution of the United States. Appellant sought in the District Court an order setting aside the Board’s decision refusing to carve a craft unit out of the existing plant unit, and further sought an order from the Court directing the Board to conduct a representation election among the employees for whom the craft unit was sought. The District Court, without opinion, dismissed the amended complaint for lack of subject matter jurisdiction and this appeal followed. This Court has jurisdiction ( 28 U.S.C. § 1291 ).

The question for this Court is whether or not the District Court had jurisdiction to review the Board’s decision refusing to sever a craft unit from the existing plant unit and to order an election for the employees within the proposed craft unit.

Appellant contends that Section 24 of the Judicial Code clothed the District Court with jurisdiction. This would be true but for the provisions of the National Labor Relations Act limiting the District Court’s general jurisdiction. Normally, under the Act, a Board order in the representation proceeding under Section 9(c) cannot be reviewed in the courts. When final orders of the Board, entered at the culmination of an unfair labor practice proceeding under Section 10 of the Act, are reviewed in the Court of Appeals, Section 9(d) provides for judicial review in that Court of the underlying determination in the rep resentation proceeding. American Fed. of L. v. National L. Rel. Bd., 308 U.S. 401 , 60 S.Ct. 300 , 84 L.Ed. 347 ; Leedom v. Kyne, 358 U.S. 184 , 79 S.Ct. 180 , 3 L.Ed.2d 210 ; Boire v. Greyhound Corp., 376 U.S. 473 , 84 S.Ct. 894 , 11 L.Ed.2d 849 .

The federal courts have consistently refused to allow direct judicial review of Board orders made in representation proceedings. In certain extraordinary circumstances, a District Court’s review of Board orders in representation proceedings has been allowed:

(1) where the Board has acted in excess of its powers, has violated a clear mandatory requirement of statute;

(2) where there is involved a public question of considerable national interest with international overtones; and

(3) where there is a substantial showing that the constitutional rights of the complaining party were violated.

The first two exceptional circumstances are described by the Supreme Court in Boire v. Greyhound Corp., supra. At page 898 of 84 S.Ct., at page 854 of 11 L.Ed.2d, we find:

In making further reference to Kyne , the Court stated at page 899 of 84 S.Ct., at page 855 of 11 L.Ed.2d:

The third exceptional circumstance is set forth by the Second Circuit in Fay v. Douds, 1949, 172 F.2d 720 , at 723:

The Courts of Appeal have considered the three exceptional circumstances in many cases, among which, pertinent here, are:

Boire v. Miami Herald Publishing Company, 5 Cir., 1965, 343 F.2d 17 , at page 20, cert. denied 382 U.S. 824 , 86 S.Ct. 56 , 15 L.Ed.2d 70 :

Leedom v. Norwich, Conn. Print. Special. & P. P. Union, 1960, 107 U.S.App. D.C. 170, 275 F.2d 628 , at page 630, cert. denied 362 U.S. 969 , 80 S.Ct. 955 , 4 L.Ed.2d 900 :

International Ass’n of Tool Craftsmen v. Leedom, 1960, 107 U.S.App.D.C. 268 , 276 F.2d 514 , at page 516, cert. denied 364 U.S. 815 , 81 S.Ct. 45 , 5 L.Ed.2d 46 :

Department & Specialty Store Emp. Union v. Brown, 9 Cir., 1961, 284 F.2d 619 , at 624:

Local 1545, United Bro. of Carpenters, etc. v. Vincent, 2 Cir., 1960, 286 F.2d 127 , at 132:

Machinery, Scrap Iron, Metal & Steel, etc. v. Madden, 7 Cir., 1965, 343 F.2d 497 , at page 499, cert. denied 382 U.S. 822 , 86 S.Ct. 53 , 15 L.Ed.2d 69 :

I

Appellant contends that the Board, in adhering in this case to the principle it laid down in Weyerhaeuser Timber Company, 87 NLRB 1076 (1949), acted in contravention of the specific statutory mandate of § 9(b) (2) of the Act. Section 9 (b) of the Act provides:

The second sentence quoted (subsection (2) of Section 9(b)) was one of several amendments contained in the Labor-Man' agement Relations Act of 1947 popularly known as the “Taft-Hartley Act”.

While Congress was considering amending Section 9(b) by the addition of subsection 2, the following appears in Senate Report 105 on S. 1126 (Vol. 1, Leg.Hist. of the Labor-Management Relations Act of 1947):

Senator Taft, in discussing the subsection (2) amendment to Section 9(b) (93 Cong.Rec. 3836 of Vol. 2, Leg.Hist. of Labor-Management Relations Act of 1947) said:

The Fourth Circuit, in N.L.R.B. v. Pittsburgh Plate Glass Co., 1959, 270 F.2d 167 , at page 172, cert. denied 361 U.S. 943 , 80 S.Ct. 407 , 4 L.Ed.2d 363 , in reviewing the effect of the 1947 amendment, stated:

In 1948, in National Tube Company, 76 NLRB 1199 , the Board considered the effect of the newly enacted Section 9(b) (2) on its determinations in representation proceedings and reached the conclusion that:

Thereafter, the Board extended its National Tube doctrine to the lumber industry.

In Weyerhaeuser Timber Company, 87 NLRB 1076 (1949), at pages 1081 and 1082, the Board stated:

In 1954, in American Potash & Chemical Corporation ( 107 NLRB 1418 ), the Board laid down these standards: (a) the intent of Congress expressed in Section 9(b) (2) would be best carried out by a finding of the Board that a craft group would be appropriate for severance purposes in cases where a true craft group is sought and where, in addition, the union involved has traditionally represented that craft; (b) Section 9(b) (2) requires the Board to give the members of the true craft group the opportunity to decide for themselves whether or not a craft unit should be severed; (c) the true craft group should not be denied separate representation merely because they are employed in a highly integrated industry with a history of industry or plant-wide bargaining. However, the Board limited the new rules it had just announced by stating that it would continue to decline craft severance in those highly integrated industries to which it had already applied National Tube and where industry or plant-wide bargaining prevailed, but announced that the National Tube doctrine would not be further extended.

In other words, the Board established the rule that if a true craft unit was sought and there was traditional representation by the union involved, it would no longer deny craft severance merely because of the integrated nature of the industry and a history of industry or plant-wide bargaining, except in those cases where it had theretofore applied the National Tube doctrine, to wit, steel, wet milling, aluminum and lumber. In these industries, the so-called “four favorite industries”, it would continue to deny craft severance where production and maintenance processes are highly integrated and where there was a history of industry or plant-wide bargaining.

In 1966, in Mallinckrodt Chemical Works ( 162 NLRB No. 48 ), the Board reversed American Potash. We quote, in part, from Mallinckrodt:

When the Board in this case refused craft severance, it did so with its National Tube and Weyerhaeuser decisions in mind. The American Potash doctrine, now repudiated by Mallinckrodt, could not have been considered because the American Potash doctrine excepted the National Tube industries, and, of course, Mallinckrodt had not been decided at the time of the Board’s decision in this case.

It is not for this Court nor for the District Court below to decide whether correct standards were established and applied by the Board in the various cases decided by it after subsection (2) was added to Section 9(b) in 1947, so long as the Board in the case at bar has not “failed to give effect to a clear statutory command * * * so as to justify intervention by the District Court in the normal process of determining an appropri ate bargaining unit under the Act.” If it is not clear in this case that the Board ignored the prohibition of Section 9(b) (2), then it matters not to this Court whether the Board’s decisions from National Tube to Mallinckrodt are correct because unless the Board flaunted a clear statutory command, plainly violated a mandatory provision of statute, the District Court may not interfere with the exercise of the Board’s expertise, it may not reach into the Board’s discretionary area of unit determination.

We turn, now, to the question, did the Board violate the prohibition of Section 9(b) (2) by adhering to the “Weyer-haeuser principle” ?

The employee group, here, seeking a craft unit, did not, under Section 9(b) (2), have an absolute right to organize separately, but was entitled to have their petition given the same consideration by the Board after the maintenance and production plant unit had been established as before the plant unit was established. The Board had the authority and the duty to decide what bargaining unit was appropriate, but in doing so, it was required to keep foremost in mind the declared policy of Congress that employees be given the fullest freedom in choosing their bargaining unit. This means that unless there were in the Board’s expert judgment sound reasons why the craft unit sought was inappropriate, the desires of the craft group must prevail. The Board may not, whether or not it considers the evidence before it, reject the application for craft severance on the ground that it had already decided, in Weyerhaeuser, that craft units were inappropriate in the lumber industry. But the Board may, as it did here, after considering the evidence before it and after a re-examination of its prior decision in Weyerhaeuser, find that the craft unit sought was inappropriate for certain given reasons, either specifying them or, as it did here, by making reference to the Weyerhaeuser decision where the reasons were fully set forth. We perceive no valid reason that would compel the Board in supporting its decision to reiterate those reasons rather than to simply employ Weyer-haeuser as a convenient frame of reference.

In such circumstances, the Board has not rejected the craft unit sought based alone upon precedent, but has decided, after considering the facts and re-examining the Weyerhaeuser decision, that the reasons previously given in Weyerhaeuser supporting the plant unit as opposed to a craft unit are still valid. We hold the Board did not violate the prohibition of Section 9(b) (2).

II

Finally, Appellant contends that the District Court has jurisdiction on the ground that the Board’s decision violated the due process clause of the Fifth Amendment to the Constitution. Appellant makes three points:

(1) That the Board’s order violated the prohibition of Section 9(b) (2) of the Act.

(2) That the Board’s refusal to permit craft severance of the lumber industry creates an arbitrary distinction and has no logical, historical, factual or legal basis.

(3) That there was no rational basis for the Board’s finding that the employees for whom craft representation was sought are functionally and administratively in the basic lumber industry.

We have already disposed of the Appellant’s first point. It seems to us that all the Appellant is saying in its second and third points is that the Board action, here, was arbitrary, unreasonable, unwise and an abuse of discretion. Appellant attempts to couch these arguments in constitutional terms. We hold the contention that the Board’s action violated the due process of law clause of the Fifth Amendment to be “transparently frivolous” (Fay v. Douds, supra).

The District Court did not have jurisdiction to review the Board’s decision refusing to sever a craft unit from the existing plant unit and to order an election of the employees within the proposed craft unit.

The order of the District Court dismissing the amended complaint for lack of jurisdiction of the subject matter is affirmed.

. 28 U.S.C. § 1337 : “The district courts shall have original jurisdiction of any civil action or proceeding arising under any Act of Congress regulating commerce or protecting trade and commerce against restraints and monopolies.” . The truck drivers sought a separate craft unit and did not favor the retention in the plant unit. They did not vote. . The Board also extended the National Tube rule to the wet milling industry (Corn Products Refining Co., 80 NLRB 362 (1948)) and to the aluminum industry (Permanente Metals Co., 89 NLRB 804 (1950)). . Cf. the Fourth Circuit’s discussion in NLRB v. Pittsburgh Plate Glass Co., supra. . Quoted portions from Leedom v. Norwich, Conn. Print. Special. & P. P. Union, 1960, 107 U.S.App.D.C. 170 , 275 F.2d 628 , at 631. . The Board, in footnote numbered 17 in the Mallinckrodt case, stated: “To the extent that the decisions in National Tube Company, supra, Permanente Metals Co., supra, Corn Products Refining Company, supra, Weyerhaeuser Timber Company, supra, and decisions relying thereon, may be read as automatically foreclosing craft or departmental severance or the initial formation of such units in unorganized plants in the industries involved, they are hereby overruled.” This Court does not so read Weyerhaeuser. Weyerhaeuser did not automatically foreclose craft severance.