[ QUOTE ]
By cooperating, I retain the possibility for minimum punishment, but by confessing I prevent the possibility of maximum punishment.

[/ QUOTE ]

I believe it's the opposite in the first case. If you defect, you allow for minimum punishment (if the other prisoner cooperates). That's the dilemma -- you have the possibility for minimum punishment by defecting, but in an iterated dilemma, a "tit for tat" cooperation is the best strategy.