Zuloaga fought against the conservatives in two campaigns in Puebla, but on 17 December 1857 he came out against the 1857 Constitution of Mexico and joined in a "coup d'état" staged by a junta of generals and leading Catholic clergy. Two days later, the wavering moderate President Ignacio Comonfort accepted the reactionary Plan of Tacubaya, thus abandoning the Constitution of 1857. Various liberals protested, including Benito Juárez, the president of the Supreme Court and constitutional vice-president, next in line to succeed to the presidency, but they were arrested and imprisoned.