 Events in Spain upended the situation in New Spain once again, with the Spanish military officers overthrowing the absolutist monarch and returning to the Spanish liberal constitution of 1812.Conservatives in New Spain who had staunchly defended the Spanish monarchy now saw a reason to change course and pursue independence.Royalist army officer Agustín de Iturbide became an advocate of independence and persuaded insurgent leader Vicente Guerrero to join in a coalition, forming the Army of the Three Guarantees.