The Seneca Nation, whose 172 tobacco retailers sell more cigarettes than any other tribe, said it would continue to oppose the state's plans, even after the ruling Monday, which upheld Judge Richard J. Arcara's denial in October of an injunction sought by the Senecas, Cayugas, Unkechaug, St. Regis Mohawks and Oneidas. Judge Arcara had issued a stay of his ruling pending appeal.