And it never happened because certain labor needs were not met and lobyists bribed Congressmen to look the other way so they could have their cabbage pickers.
Unless you have a system where the Guest Workers are limited to clearly defined sectors, you will have lobbyists bribing Congress to continue to look the other way about the border and we will continue to have illegal aliens flooding ALL blue collar sectors.
That will happen anyway, because business is grimly determined to have totally uncontrolled immigration. The kicker to their bottom line is too strong to overcome except with absolute certainty of ineluctable, dire punishment.
So far, the failure to enforce has emboldened them to the point of piracy; they're almost as brash as the narcotraficantes.