From a reader:

No, you absolutely may not question Howard Zinn’s patriotism. You can justify terrorism, rationalize Stalinism, long for Communism, write hagiographies about Castro, but the one sin you cannot commit is to question someone else’s patriotism. Remember that time in the debates where George W. Bush said to John Kerry “You aren’t patriotic”, and then millions of dumb midwesterners went out and voted for Bush because he said that? Anyway, expressions such as Zinn’s are the best actualization of patriotism one can find – he’s utilizing the rights guaranteed to him under the very first, and best, Amendment to the Constitution. If you, Mr. Goldberg, want to spend your Fourth of July grilling hamburgers, waving flags, and watching fireworks explode, well, that’s not patriotic, that’s just the simple-minded orgy of the hoi polloi. But if you spend your Fourth renouncing America, or condemning flag-wavers, or soaking the American flag in a jar of urine, then drying it out and burning it while using Virginia’s copy of the Constitution as kindling, why, that’s as patriotic as it gets.

Update: Oh, and here’s an old G-File I wrote on the prohibition on questioning patriotism.

Clarification: I’m pretty sure the reader posted above is being sarcastic, for those who think he might be serious.