States that the rising cost of wages and capital is also constraining capitalist systems as more and more unions and international organizations demand that workers' rights be respected. Likewise, taxes are becoming increasingly problematic for both individuals and investors. Finally, environmental awareness is growing among contemporary social movements, and concern about global warming limits capitalists from expanding their work. Wallerstein's theory is, in its essence, very Marxist. It doesn't necessarily propose that capitalism is bad; it simply predicts that at some point in time this system will face a crisis. This theory does not necessarily predict that capitalism as a mode of production is likely to survive the crisis even if it may be profoundly weakened by it. Marxist theory explains the potential crisis by announcing the weakness of the capitalist system and stating that only with a revolutionary movement by a united working class can capitalism be overcome.