Krugman would be tough to oppose on any substantive grounds. He has a Nobel Prize in economics (also the John Bates Clark award for best economist under 40). The New York Times columnist is probably the best-known living economist in the United States, and perhaps the world.
Krugman has been right about the major problems facing our economy, where many other economists and much of the business press have been wrong. A few examples: he wrote about the housing bubble before it collapsed and caused the Great Recession; he has forecast and explained that large budget deficits and trillions of dollars of “quantitative easing” (money creation) would not cause inflation or long-term interest rates to rise; and that the “confidence fairies” would not reward governments that pursued austerity in the face of recession.
Most importantly, Krugman is on the side of the majority of Americans. He has written extensively in favor of policies that favor job creation, explained the folly of budget cutting in the face of a weak economy, and opposes cuts to social security and Medicare benefits.