My views are more akin to the nineteenth-century liberal philosophy espoused by Milton Friedman, especially in his Capitalism and Freedom. In that wo… - Robert Barro

In fact, the only person to rival Friedman for policy influence in the twentieth century is John Maynard Keynes, who had a strikingly different view of the role of government. Keynes was influential because he advocated more government intervention into what he perceived as poorly functioning private economies caught up in the Great Depression. In contrast to Keynes, Friedman put the main blame for the Depression on government failures, especially of monetary policy. Hence, the Depression did not make Friedman a fan of big government. He also found in the Federal Reserve’s failure to prevent deflation an argument in favor of monetary rules. As the world evolved— with low inflation becoming the major mission of central banks and free markets and secure property rights becoming the main policies to promote economic growth—Friedman surely won the intellectual battle.

One troublesome aspect is the place of rational expectations macroeconomics in the often political debate over Keynesian economics. At least implicitly, many people feel that what's bad for the rational expectations viewpoint is good for the Keynesian one, and vice versa. But it is hard to see how the problems in using the rational expectations approach to explain monetary nonneutrality can alleviate the theoretical and empirical shortcomings of the Keynesian model.

Mundell’s models allowed a significant role for fiscal policy, especially under fixed exchange rates. However, the treatment was entirely Keynesian—an increased budget deficit operated solely by raising the aggregate demand for goods. Moreover, increases in government spending and cuts in taxes had pretty much the same effect on the economy.