Krugman has Jewish roots, but is quite critical of religion in politics and economics, so we're going to default him an agnostic.
Krugman is a proud liberal and has been highly critical of conservatives and Republicans, particularly their economic policies.
Paul Krugman was born into a Jewish family on Long Island, New York.
Krugman is incredibly critical of religion. While it is hard to determine whether or not he is an atheist, agnostic, or just a non-practicing Jew, Krugman certainly believes that religion has no place in politics and economics.
He has said:
[Conservative economic thought is] increasingly dominated by people who believe truth should be determined by revelation, not research.
While we could deduce from this quote that Krugman feels political and economic policy should be driven by facts and real-world conclusions, we can also see which side of the political fence he's on–liberalism. His blog for the New York Times is even called "The Conscience of a Liberal."
These sorts of things have made Krugman one of the most widely-hated and controversial economists of our time and Fox News actually declared him a "menace to society," to which Krugman replied:
I'm honored…always glad to be of service.
Krugman was highly critical of the Bush administration's economic policies, particularly tax cuts–though he was critical of Obama for bailing out the banks and the fact that his stimulus plan was too small for an economy as large as the U.S.'s. What this all means is that Krugman sticks to his economic ideas despite which party is in power despite claims that:
[Krugman is] a sort of ivory-tower folk-hero of the American left—a thinking person's Michael Moore…[and] his relentless partisanship is getting in the way of his argument.
As a liberal economist, Krugman has associated himself with the Occupy Wall Street movement and called for the imprisonment of some of the perpetrators of the 2008 financial crisis. Beyond that, he's been a staunch supporter of the welfare state and a critic of austerity measures in Europe.
Krugman is a complex and prolific intellect. And though his theories tend to be consistently leftist, he's more of an economist than a politician so he's tough to nail down.
He leans towards the Keynesian school of economic thought, meaning Krugman thinks there should be more government control of the economy–to some, this is a scary thought, particularly libertarians and proponents of small government.