Although many have said that Siqueiros' artistic ventures were frequently "interrupted" by his political ones, Siqueiros himself believed the two were intricately intertwined.
By 1921, when he wrote his manifesto in Vida Americana, Siqueiros had already been exposed to Marxism and saw the life of the working and rural poor while traveling with the Constitutional Army.
In "A New Direction for the New Generation of American Painters and Sculptors", he called for a "spiritual renewal" to simultaneously bring back the virtues of classical painting while infusing this style with "new values" that acknowledge the "modern machine" and the "contemporary aspects of daily life".
The manifesto also claimed that a "constructive spirit" is essential to meaningful art, which rises above mere decoration or false, fantastical themes.
Through this style, Siqueiros hoped to create a style that would bridge national and universal art.
In his work as well as his writing, Siqueiros sought a social realism that at once hailed the proletariat peoples of Mexico and the world while avoiding the clichés of trendy "Primitivism" and "Indianism".

In 1922, Siqueiros returned to Mexico City to work as a muralist for Álvaro Obregón's revolutionary government.
The then Secretary of Public Education José Vasconcelos made a mission of educating the masses through public art, and hired scores of artists and writers to build a modern Mexican culture.
Siqueiros, Rivera and José Orozco worked together under Vasconcelos, who supported the muralist movement by commissioning murals for prominent buildings in Mexico City.
Still, the artists working at the Preparatoria realized that many of their early works lacked the "public" nature envisioned in their ideology.
In 1923 Siqueiros helped found the Syndicate of Revolutionary Mexican Painters, Sculptors and Engravers, which addressed the problem of widespread public access through its union paper, El Machete.
That year the paper published – "for the proletariat of the world" – a manifesto, which Siqueiros helped author, on the necessity of a "collective" art, which would serve as "ideological propaganda" to educate the masses and overcome bourgeois, individualist art.

Soon after, Siqueiros painted his famous mural Burial of a Worker (1923) in the stairwell of the Colegio Chico.
The fresco features a group of pre-Conquest style workers in a funeral  procession who are carrying a giant coffin, decorated with a hammer and sickle.
The mural was never finished and was vandalized by students at the school who did not agree with the overtly political subject matter in the painting.
Eventually, the entire painting was whitewashed by the new Minister of Education who succeeded Vasconcelos.
But as the union became ever more critical of the revolutionary government, which had not instituted the promised reforms, its members faced new threats to cut funding for their art and the paper.
A feud within the union over whether to cease publishing El Machete or lose financial support for the mural projects left Siqueiros at the forefront, as Rivera left in protest of the decision to uphold politics over artistic opportunity.
Despite being let go from his post under the Department of Education in 1925, Siqueiros remained deeply entrenched in labor activities, in the union as well as the Mexican Communist Party, until he was jailed and eventually exiled in the early 1930s.

After spending many years in Mexico and heavily involved in radical political activities, Siqueiros went to Los Angeles in 1932 to continue his career as a muralist.
Working in a collective unit that experimented with new painting techniques using modern devices such as airbrushes, sprayguns and projectors, Siqueiros and his team of collaborators painted two major murals.
The first, Street Meeting, was commissioned for the Chouinard School of Art.
It depicts a group of workers of mixed ethnicities listening to an angry labor agitator's speech during a break in the workday.
The mural was washed over within a year of its unveiling—due both to weather-related technical
Although many have said that Siqueiros' artistic ventures were frequently "interrupted" by his political ones, Siqueiros himself believed the two were intricately intertwined. By 1921, when he wrote his manifesto in Vida Americana, Siqueiros had already been exposed to Marxism and saw the life of the working and rural poor while traveling with the Constitutional Army. In "A New Direction for the New Generation of American Painters and Sculptors", he called for a "spiritual renewal" to simultaneously bring back the virtues of classical painting while infusing this style with "new values" that acknowledge the "modern machine" and the "contemporary aspects of daily life". The manifesto also claimed that a "constructive spirit" is essential to meaningful art, which rises above mere decoration or false, fantastical themes. Through this style, Siqueiros hoped to create a style that would bridge national and universal art. In his work as well as his writing, Siqueiros sought a social realism that at once hailed the proletariat peoples of Mexico and the world while avoiding the clichés of trendy "Primitivism" and "Indianism".
In 1922, Siqueiros returned to Mexico City to work as a muralist for Álvaro Obregón's revolutionary government. The then Secretary of Public Education José Vasconcelos made a mission of educating the masses through public art, and hired scores of artists and writers to build a modern Mexican culture. Siqueiros, Rivera and José Orozco worked together under Vasconcelos, who supported the muralist movement by commissioning murals for prominent buildings in Mexico City. Still, the artists working at the Preparatoria realized that many of their early works lacked the "public" nature envisioned in their ideology. In 1923 Siqueiros helped found the Syndicate of Revolutionary Mexican Painters, Sculptors and Engravers, which addressed the problem of widespread public access through its union paper, El Machete. That year the paper published – "for the proletariat of the world" – a manifesto, which Siqueiros helped author, on the necessity of a "collective" art, which would serve as "ideological propaganda" to educate the masses and overcome bourgeois, individualist art.
Soon after, Siqueiros painted his famous mural Burial of a Worker (1923) in the stairwell of the Colegio Chico. The fresco features a group of pre-Conquest style workers in a funeral  procession who are carrying a giant coffin, decorated with a hammer and sickle. The mural was never finished and was vandalized by students at the school who did not agree with the overtly political subject matter in the painting. Eventually, the entire painting was whitewashed by the new Minister of Education who succeeded Vasconcelos. But as the union became ever more critical of the revolutionary government, which had not instituted the promised reforms, its members faced new threats to cut funding for their art and the paper. A feud within the union over whether to cease publishing El Machete or lose financial support for the mural projects left Siqueiros at the forefront, as Rivera left in protest of the decision to uphold politics over artistic opportunity. Despite being let go from his post under the Department of Education in 1925, Siqueiros remained deeply entrenched in labor activities, in the union as well as the Mexican Communist Party, until he was jailed and eventually exiled in the early 1930s.
After spending many years in Mexico and heavily involved in radical political activities, Siqueiros went to Los Angeles in 1932 to continue his career as a muralist. Working in a collective unit that experimented with new painting techniques using modern devices such as airbrushes, sprayguns and projectors, Siqueiros and his team of collaborators painted two major murals. The first, Street Meeting, was commissioned for the Chouinard School of Art. It depicts a group of workers of mixed ethnicities listening to an angry labor agitator's speech during a break in the workday. The mural was washed over within a year of its unveiling—due both to weather-related technical
David Alfaro Siqueiros