MINNEAPOLIS (AP) --- The fight between Northwest Airlines Corp. and its flight attendants is about to turn into a fight between their lawyers.Flight attendants announced on Tuesday that they'll conduct random, unannounced strikes beginning at 10:01 p.m. EDT on Aug. 15 unless Northwest backs off the new contract it imposed on them Monday after workers voted down a negotiated agreement.But would a strike be legal?The union says its workers can't be forced to work under terms they didn't agree to. Northwest says it had a bankruptcy judge's permission to impose those terms, and that any strike is barred by the Railway Labor Act, which governs airline labor. .