Zakaria hit the nail on the head in describing why President Bush's foreign worker plan, while sounding good, is destined to cause more problems than it solves. He pointed out the glaring fact that programs that import labor while withholding the promise of citizenship as an end result has led to large withdrawn communities that, seeing no point in it, avoid assimilation.
I doubt many conservative groups concerned about immigration have forgotten the images of Muslim youths setting fire to cars in the suburbs of Paris.
It's not likely the President' staff missed the problems Europe has experienced. It's likely the President is just trying to punt on this one. His base doesn't like it, they see it as a precursor to amnesty, but it's a moderate-sounding idea if you don't look too deep. For this administration, sounding good will always win out over actually being sound.
Kevin Drum hits on this as well.