(taken from "Evans on Chess", Chess Life, September 1994) BTW: I have a PDF of the actual magazine, the original article is bigger so I'll convert the article to the bl0g in the next few days...
BUSTING BOBBY'S BUST
Saratoga Springs, New York
Q: In their first game at Mar del Plata, 1960, Bobby Fischer lost to Boris Spassky's King's Gambit (My 60 Memorable Games, No. 18). Shortly thereafter Bobby wrote a famous article in which he claimed to "refute" the gambit. Was he right? By now we should know the answer. Where can I get a copy of his article?
A: "While trying to figure out what was going on in Spassky's head, I blundered and lost the game!" wrote Fischer. His "Bust to the King's Gambit" kicked off the first issue of the American Chess Quarterly [Summer 1961], a magazine I once edited that conked out in 1965. His bolt shot was heard round the world; Soviet analysis promptly sought an antidote.
The article began: "The refutation of any gambit begins with accepting it. In my opinion the King's Gambit is busted. It loses by force: 1. e4 e5 2. f4 exf4 3. Nf3 d6! This is the key to a troublesome position, a high-class waiting move. I played 3. ... g5 against Spassky, but this is inexact because it gives White drawing chances in the ensuing ending."
Here's Fischer's main line (transposing into the Hanstein Gambit): 4. Bc4 h6 5. d4 g5 6. O-O Bg7 7. c3 Nc6 8. Qb3 Qe7 9. h4 Nf6 10. hxg5 hxg5 11. Nxg5 Nxe4 12. Bxf7+ Kd8 13. Nxe4 Qxe4 14. Bxf4 Nxd4 (diagram).
"And Black wins... "concluded Fischer, with a little inside joke: "Of course White can always play differently, in which case he merely loses differently. (Thank you, Weaver Adams!)" This was a reference to an American master who had written a book called "White to Play and Win" (based on using the Bishop's Opening, which was later revised to the Vienna Game).
The Fischer Defense is still okay but doesn't win by force. In Modern Chess Openings (10th edition, 1965, page 99) I cited one flaw: 15. Bg5+ Kd7 16. Qd5 Ne2+ 17. Kf2 Qg4 with an equal position.