This is because Cain himself probably has no idea what he's talking about. It is clear he doesn't understand the issue and the Federal responsibility for immigration enforcement.
Cain is just making it up as he goes along. He bluffed his way this far with motivational speaking skills, but on the issues he basically doesn't know what he's talking about. Fortunately, Cain will not be the nominee.
That's been obvious for a very long time.
Don’t be so critical. This is just the seedling of a “BOLD” immigration plan. It needs time to grow. Once it has a catch phrase or slogan it will become boldly viable. Then like his 999 plan, “once you understand it, you’ll demand it.” /sarc/