I figured that out a long time ago. But now my friends Larry Ribstein, Jonathan Adler, JW Verret, and Todd Henderson have figured it out too. I won't bother you with the merits of the argument, because you can't have an argument--let alone a conversation--with someone with Delong's consistent pattern of, as Adler puts it, "selective editing" and misrepresenting his opponent's positions. To quote Adler again, "Yes, this is the same Professor DeLong who repeats baseless accusations against other academics and then, when asked to substantiate his charges, selectively edits his comment threads and then dissembles about said editing when called on it."
I believe it was George Bernard Shaw who said "I learned long ago, never to wrestle with a pig. You get dirty, and besides, the pig likes it."
Hence, I agree with Larry that "a discussion with the likes of Brad DeLong is not productive." With luck, this'll be the last time his toxic style of intellectual thuggery and execrable personality will be mentioned in these pages.