It should serve the public interest, which is good enough for policy debates.
This is absolutely false. Policy debates universally assume that it will serve the public interest, despite experience and extensive research in public choice economics.
The result is that we get policies that aren't crafted to be robust to corruption and bad incentives, and that gets us to the state we're in today.
Any policy debate should include discussion of what could go wrong, what the effects of that would be, and what we could/should do to prevent that.
I guess I wasn't clear enough. My point is that, in a policy debate, whining about how government has not served the public interest in the past is counterproductive except insofar as it helps to prevent all the crap you enumerated. What we're both saying is that policy debates are about how to write policies that actually serve the public interest, instead of falling into some perverse incentive trap.
