Kevin Williamson explains for National Review Online readers why in at least one instance — the Trans-Pacific Partnership trade agreement — President Obama is on the right side of an economic issue.

The dispute over TPP finds Barack Obama at odds both with congressional Democrats and with progressive activists, and making uncomfortably common cause with the most reliable partisans of free trade: most everybody who hates his guts.

Some Republicans have reservations about investing the president with “fast track” authority — meaning that he would be empowered to negotiate a deal that would then get a simple yes/no vote in Congress, which turns out to have a say in international affairs after all — because they are mindful of this imperial president’s habitual infliction of violence on the Constitution and of his seething contempt of the legislative branch in which he served for approximately eleven minutes. But it is unlikely that Republicans will in the end say no to a trade deal.

Professor [Paul] Krugman’s case against TPP is, in brief, “meh.” He offers very little in the way of substantive criticism of the proposed accord, instead pooh-poohing it as modest, something that might add no more than 0.5 percent, and probably not even that, to the incomes of the participating nations. Those nations represent more than one third of the world’s economic output, though. Brad DeLong of the Washington Center for Equitable Growth addresses Professor Krugman’s sniffing directly: What if the additional growth were only half that 0.5 percent number? “In a Pacific region whose GDP is now approaching $30 trillion/year,” he writes, “that is $75 billion/year. Capitalize that at 4 percent/year and we get a net addition to world wealth of $3 trillion. That is indeed a very small number relative to the wealth of the world both now and discounted into the future. But that is a rather large number compared to other things the U.S. government might do this year. So why not grab for it?”

Why not?

Because we are not talking about economics, or even about politics – we are talking about hatred. The Left hates international trade, especially with the sweaty Yellow Peril that haunts its fever dreams — get more than five Democrats in a room and it turns into a meeting of the Asiatic Exclusion League — and Professor Krugman hates the Republicans who are enthused about international trade. Thus the abundance of his sneering and the scantiness of his analysis.