Critics of MECha regard the phrase "Por La Raza todo, Fuera de La Raza nada" as ethnocentric and racist. This phrase appears in El Plan Espiritual de Aztlán as the official "slogan" of MEChA. MEChA members themselves differ in their interpretations of "La Raza". While some use the term to strictly refer to only mestizos and Chicanos, others use it to mean all Hispanics and minorities. Jose Vasconcelos defined the "La Raza" racial supremacy doctrine for Hispanics and mestizos in his book, "La raza cósmica". During WWII, Vasconcelos was one of the most prominent Nazi agents and propagandists in Mexico. A possible origin of the phrase is the Cuban Revolution, which used the similar slogan "Por la revolución todo, fuera de la revolución nada!" According to the official MEChA website, the organization "does not exclude membership based on socio-economic status, gender, race, or orientation."