The baseline reality for any discussion of where we’re headed is that from 1870 to 2008, the U.S. economy has had average GDP productivity growth of about 3% and about 2% on a per-person basis. Despite displacements—wars, depressions—we’ve always returned to this solid upward trend. From 1870 till recently, real income per person has increased by a factor of 12—”an ongoing miracle,” Prof. Lucas notes, “mainly due to free-market capitalism.”…

Forgotten in most discussions of the U.S.-Europe comparison is that for the first 70 years of the 20th century, continental Europe’s growth rose alongside that of the world-leading U.S. and U.K., especially after World War II. Through the 1960s, he says, there was every reason to expect a common, high living standard for all of us. Then, “in the 1970s, their catch-up stalled.”

A 20% to 40% gap in income levels emerged between the U.S. and Europe, reflecting a lowered European work effort. In Prof. Lucas’s view, that gap represents the cost (largely taxes) of financing a larger welfare state from 1970 onward. Other economists, he says, have cited a 30% loss in GDP per person in Western Europe since the 1970s…

“If we’re going to move to a European welfare state,” says Prof. Lucas, “we’re going to have to pay a European price.” And that price could be a permanently lower level of GDP per person. The U.S.’s amazing 100-year ride would slow.