"So how about just open the door to anyone willing to put down a refundable entry deposit (say, $2,000) in return for a biometric work card?"
Great idea, Holman! I bet you spent 60, maybe even 90 seconds thinking through all the possible ramifications of that plan.
According to the CIA World Factbook, in 2004, there were 4,976,000,000 people in this world living in countries with average per capita GDPs lower than Mexico's. And, two polls conducted by the Pew Hispanic Trust showed that over 40% of Mexicans say they would immigrate to America if it were legal. And, just about anybody could borrow $2,000 based on their future earnings in America.
So, where exactly would we put two billion new immigrants?
Well, obviously, we don't have to worry about 2,000,000,000 newcomers. Probably by the time 10 percent of that number had jostled their way in, conditions in America would have descended to the level of their Third World homelands, so there'd be no more incentive to immigrate.
Have you noticed how Open Borders advocates like to show off in public that they have not spent done anything so disreputable as thinking hard about immigration? Mindless insouciance about immigration proves that you, personally, don't have to worry about it, that you are above it all. Nobody from Chiapas is going to take Holman W. Jenkins Jr.'s job, no sirree!