The slave owners claimed that they were the rightful owners of the slaves and that they should be dealt with under the Spanish Law. The vessels, and the goods on board were the property of Spanish subjects in Havana and the "Negroes" in question were certified at that time by a document signed by the Governor General of Cuba to be property of Spanish subjects (Argument of the Government). President Martin Van Buren was in favor of handing over the Africans to Spain. He felt if he freed the slaves, he could lose the support from the South and with elections coming up and he could not afford that. He feared that releasing the Africans would have unexpected consequences due to the revolts and uprising of anti-slavery happening during that time. On February 10, 1840 the Hartford Courant published an article attacking President Martin Van Buren for his stance on the Amistad case and he stated "Martin Van Buren is playing the part of a tyrant with a high hand - else why this tampering with our courts of justice". People noticed that Martin Van Buren's interest was only for his own benefit and his stance on the Amistad case only favored him. .
The Spanish slave-owners had the "evidence" to take the Africans but because during this time abolitionist activity was at its peak the court got involved and Roger Baldwin took the case. Roger Baldwin was a New Haven with a reputation of defending the unfortunate (Biographies of players in the Amistad Affair). Baldwin argued that "Ruiz and Montes were the criminals, not the Africans who fought for their freedom, and that the two Cubans deserve the penalty of death for piracy" (Biographies of players in the Amistad Affair). In his argument to the court he stated these Negroes are not slaves, but were kidnapped Africans, who, by the laws of Spain itself, are entitled to their freedom. They were kidnapped and illegally carried to Cuba, and detained and restrained on board of the Amistad; there is no evidence to say, that they are pirates or robbers (Supreme Court Argument and Decision).