Just a whimsical thought...any lawyer worth his/her salt can construct an appropriate argument for either side of any case...What would be your's in favor of the East?
I disagree that any argument, no matter how ridiculous, is "appropriate" to pursue. Lawyers can get sanctioned for putting forth arguments that have no reasonable basis in law or fact. When an argument is too weak, it is frivolous, and lawyers can get punished for clogging up the courts with such nonsense. Sometimes a lawyer "worth his salt" has the responsibility to tell his client that the client simply does not have a case.
Such is the case here. Similar to a lawyer explaining to a client after a jury trial that the jury decided against him, here a lawyer's duty is to explain to East that they submitted to binding arbitration, and must abide by the arbitrator's decision. (Of course, this should have been explained before starting the whole process.) There are occassionally narrow grounds to go to court to vacate the arbitrator's decision which should be explored if they would conceivably apply, but as has been discussed exhaustively on this site, those grounds do not exist in this case.
Sure a few complaints could be filed seeking to vacate the arbitration, but those would soon get dismissed, and if that behavior were to continue, sanctions would follow.
But for the sake of argument, I suppose the least worst argument to try to get the arbitration award thrown out would be to argue the arbitrator somehow abused his discretion and exceeded the authority granted to him by ALPA in totally disregarding the guidelines that were supposed to be followed, and that the new seniority list was created arbitrarily -- i.e., that the list is not based on any reasonable factors and no reasonable arbitrator would have come up with such a list. (In fact, I think that is basically what East was trying to do in filing the complaint in the D.C. courts a couple of months ago, which I seem to recall was removed to federal court -- whatever happened with that?) However, that would still be a losing argument because the record would not support it. The facts of this case do not even come close to the legal standard necessary to overturn an arbitration award for being arbitrary or for an arbitrator exceeding his authority.
So we're back to Square One, which is explaining to East that ultimately they will have to come to terms with the award one way or another.