nates any prospect of preclusion, id. at 1282-83. To cut out of the circle one must inquire whether the disputed component of the agency decision has the prerequisites for collateral estoppel independent of appealability; if not, then collateral estoppel cannot be the basis for appealability.
We need not here explore the conditions under which an administrative determination might have an issue-preclusive effect in a later judicial proceeding. To have such an effect, it must not only satisfy the ordinary requirements of collateral estoppel but must also result from a process sufficiently similar to a judicial proceeding. See Restatement (Second) of Judgments § 83 (1982). Here, the FMC’s decision on the “allocation” issue lacks one of the ordinary prerequisites: it was not necessary to the judgment. See, e.g., Montana v. United States, 440 U.S. 147, 153, 99 S.Ct. 970, 973, 59 L.Ed.2d 210 (1979); Abbs, 963 F.2d at 924. Thus, quite independently of their lack of appealability, FMC’s findings on allocation can give Sea-Land no reasonable concern about preclusive effect. Indeed, ongoing FMC proceedings show that the agency understands this: while maintaining its position on § 10(c)(6), it does not suggest that the findings are preclusive. See 63 Fed.Reg. 3115, 3116 (1998).
Neither the general interpretation of § 10(e)(6), nor the specific findings about these agreements, makes the FMC’s decision adverse to Sea-Land and APL. Without an adverse judgment, or extraordinary circumstances such as enunciation of a rule with the kind of injury inflicted in IBEW, objectionable interpretations and findings are not enough to ground an appeal.
That does not mean that Sea-Land and APL had no way of challenging the FMC’s decision on the allocation issue. The Sealift Command’s appeal, No. 97-1084, is properly before us, and Sea-Land and APL have intervened in support of the FMC. They could, as intervenors, properly have urged affirmance or remand on any ground presented to the FMC, including their argument about the allocation clause. See Showtime Networks, Inc. v. FCC, 932 F.2d 1, 4-5 (D.C.Cir.1991). This method of presenting issues, defensively and in the alternative, is the usual way for prevailing parties to protect themselves on appeal from the risk that the appellate court may reverse the decisions attacked by the appellants. Sea-Land and APL did not employ it; their brief as inter-venors, at 2, explicitly restricts itself to the question of whether MarAd orders are “law of the United States.”
An alternative risk-control device would have been a “conditional” cross-appeal, asking to be heard only if we accepted the Sealift Command’s argument about the “except” clause. While some circuits treat conditional cross-appeals as outside their jurisdiction in these circumstances, evidently on the ground that parties may rely on the more conventional intervention procedure, see, e.g., Great American Audio Corp. v. Meta-com, Inc., 938 F.2d 16,19 (2d Cir.1991), mos.t apparently accept them. See generally 15A Charles A. Wright, Arthur R. Miller & Edward H. Cooper, Federal Practice & Procedure § 3902 at 78-79 (1992) (collecting cases).
The carriers in fact framed their appeal unconditionally, but this circuit, in Showtime, 932 F.2d at 5, appeared willing to entertain even a conditional cross-appeal styled as an unconditional petition for review—if the feared judicial embrace of the appellant’s position materialized. See also Hartman v. Duffey, 19 F.3d 1459, 1465-66 (D.C.Cir.1994) (discussing conditional cross-appeals). Thus, if we had accepted the Sealift Command’s position on § 10(c)(6)’s exception, we would hesitate to reverse the FMC without considering Sea-Land’s and APL’s claims on the “allocation” issue.
But where, as here, the losing party’s theories are rejected, courts appear uniformly to dismiss a conditional cross-appeal. Showtime reaches this result, noting' to be sure that the party bringing the appeal conceded its mootness in such circumstances. See 932 F.2d at 5; see also, e.g., Maschka v. Genuine Parts Co., 122 F.3d 566, 572 n. 4 (8th Cir.1997) (dismissing cross-appeal as moot after affirming district court); Wilson v. New York, 89 F.3d 32 (2d Cir.1996) (“no occasion to reach issues” without reversal); Hartman,