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".