By Fareed Zakaria, CNN
I've been watching the Republicans on the campaign trail and what strikes me so far is that conservatives in America have gone through a strange transformation.
It used to be that conservatism was a hard-headed set of ideas rooted in reality.
Unlike the abstract theories of Marxism and socialism, it started not from an imagined society, but from the world as it actually exists.
"This is the way things work," conservatives would patiently explain to wooly headed liberal professors. "Whatever you may want it to look like, this is what it really looks like."
But consider the debates over the economy these days. The Republican prescription is cut taxes - slash government spending, then things will always bounce back.
Now, I would like to see lower tax rates in the context of simplification and reform, but what is the actual evidence that massive tax cuts are the single best path to revive the U.S. economy? Taxes as a percentage of GDP are at their lowest levels since 1950. The U.S. is among the lowest taxed of the big industrial economies.
So the case that America is grinding to a halt because of high taxation is not based on facts, either past or present. It is simply a theoretical assertion.
The rich countries after all are in the best shape right now with strong growth and low unemployment are ones like Germany, Denmark and Canada - none characterized by low taxes.
Meanwhile, many Republican businessmen have told me that the Obama administration is the most hostile to business in 50 years.
More than that of Richard Nixon, for example, who presided over tax rates that reached 70 percent, regulations that spanned whole industries like airlines and telecommunication and who actually instituted price and wage controls?
In fact, right now any discussion of any government involvement in the economy - even to build vital infrastructure - is impossible because it is a cardinal tenet of the new conservatism that such involvement is always and forever bad.
That's the theory.
Meanwhile, in practice across the globe the world's fastest growing economy, China, has managed to use government involvement to create growth and jobs for three decades.
From Singapore to South Korea to Germany, evidence abounds that some strategic actions by governments can act as catalysts for free market growth.
But conservatives now resemble the old Marxists who refuse to look at actual experience. "I know it works in practice," the old saw goes, "but does it work in theory?"
Republicans often praise businessmen. Well, one of the first steps any business now takes when confronting a problem is to ask, "How are other companies around the world handling this? Is there a best practice we can learn from?" But in any area, from infrastructure to health care to education, to ask these questions is heresy on the right.
It's a shame. I think we need smart, market-friendly conservative reforms that streamline government, cut costs in health care and empower individuals, but they need to be rooted in reality, drawn from best practices around the world and based on practical measures of what seems to work.
What we have instead are policies that are simply recitations of some free market theory taken out of some book based on no actually existing national economy.
It turns out conservatives have become the wooly headed professors after all.
For more on this, you can read my column in this week's TIME Magazine.