Drawing Parallels But Missing the Point

At Reason, Julian Sanchez draws attention to Bush's strange comparison of prohibition to illegal immigration. Bush makes a very good point: alcohol prohibition was a miserable failure, as it created a horrible black market for something that people were going to find a way to get whether it was legal or illegal. Interestingly, he completely misses the obvious parallel to the drug war and instead compares this to illegal immigration (which is also true, of course, but not quite as tight an analogy). Julian sums it up this way:

Sound point, sound point. Except, I've got a niggling feeling that this analogy is even more apt for some other public policy question... what could it be, what could it be?

Hm. I'm stumped.