Keynesian economy is sort of "socialistic capitalism" meaning that it is capitalism, but more benefits are given to the workers, and etc, so that they have more money to buy stuff, which in the end will ultimately preserve capitalism. Critics have argued that Roosevelt's New Deal was too socialistic, and that it was even anti-capitalistic because the government took a huge involvement in managing the economic affairs of a nation. But then new revisionists would argue that Roosevelt only did what he did so that he could ultimately preserve capitalism.
Just my two cents