Which presidential candidate, in this populist primary year, is best on the all-important issue of global trade? Economist David Ranson says it's John McCain.

On willingness to let the markets rather than government drive the adaptation of the economy to foreign competition, Messrs. McCain and Obama outscore Mr. Romney. On willingness to confront politically entrenched but trade-unfriendly policies such as farm subsidies, Mr. McCain beats both Messrs. Obama and Romney.

On rhetoric at least, McCain wins. One assumes that, when it comes to policy, some of Romney's mildly populist rhetoric would be heavily tempered, or indeed completely erased, by his substantial business and investment experience. McCain's soothing stance on international trade, meanwhile, is contradicted by his past unwillingness to let Americans engage in free trade within our own borders: See his proud and flagrant opposition to the Bush tax cuts and his penchant for regulating and bullying businesses. One can only hope that the economic conservatives now surrounding McCain -- Phil Gramm, Jack Kemp, Rudy Giuliani, Steve Forbes -- will steer him toward free trade at home as well as abroad.

Sen. Clinton was known to have opposed her husband's important Nafta achievement, which acted as a huge tax cut for all of North America. Ranson summarizes her view:

Mrs. Clinton believes in "smart trade." As president she would appoint an official to ensure that "provisions to protect labor and environmental standards" are enforced by international bodies like the WTO and the International Labor Organization. She proposes a "time out" on future trade agreements, and a reconsideration of existing deals -- including Nafta.

Obama mostly does not pander to the left on the issue but acknowledges reality:

"Global trade is not going away, technology is not going away, the Internet is not going away. And that means enormous opportunities, but [it] also means more dislocations." In a 2005 essay he said: "It's not whether we should protect our workers from competition, but what we can do to fully enable them to compete against workers all over the world."

On the other hand, he and Sen. Clinton supported the outrageous Schumer-Graham 27.5% tariff on China that shows its ugly head about every six months. A more self-destructive piece of legislation can hardly be imagined.

Gov. Huckabee, meanwhile, is a serial China basher and "fair" trader who wants economic and energy "independence."

Last week former UK prime minister Tony Blair urged the U.S. candidates not to submit to the protectionist temptation. At least on that point, we heartily agree.