In this fifth and final part of the Uncommon Knowledge interview with economists John Taylor and Ken Judd, I note that federal spending as a proportion of GDP fell smartly under presidents Reagan and Clinton, a major, and, by the time Clinton left office, bipartisan achievement, but that spending has climbed under Bush—and, given the shape of entitlement programs, looks certain to go right on climbing under his successor. What, I ask, is the next president to do? Raise taxes?

Ken Judd, who finds Senator Obama beguiling, wouldn’t object. But John Taylor, who, not incidentally, is Senator McCain’s economic adviser, most certainly would. “It’s very important,” Taylor says, “to make the [Bush] tax cuts permanent.”

An entertaining and informative tussle—and John McCain’s economic adviser fights with reassuring vigor.