Let them all in? Laying a thought experiment on top of a thought experiment

Jeff Spross of ThinkProgress thinks we should give all kids who arrive on our borders immediate legal status. Josiah Neeley of the Texas Public Policy Foundation responds (on Twitter) by dangling a bit of bait: "why not let in anyone who wants come? Spross suggests that the U.S. could handle the influx if it had to or wanted to. Neeley then asks, "How many do you think would come if we accepted anyone who wanted to come?"

This recalled me to a thought experiment that seems apropos, though I'm not sure why -- maybe because it suggests, indirectly, how much running room we have. Courtesy of James Fallows:

I mentioned yesterday that Thomas Barnett had given a realistic brief appraisal of China's strengths and weaknesses in an NPR interview. A point I particularly liked was this tip for comparing American and Chinese scale:

If Americans wanted to imagine what it would take to be "strong" in the way China currently is, he said, all we'd have to do is think of moving the entire population of the Western Hemisphere into our existing borders. Every single Mexican. (Rather than enforcing the southern border, we'd require everyone to cross it, headed north.) Every Haitian, Cuban, and Jamaican. Everyone from Central America. All 190 million from Brazil. And so on. Even the Canadians. China, by the way, is just about the same size as the United States, though a larger share of its land area is desert, mountain, or otherwise nonarable.

If we did that, we'd be up to about a billion people -- and then if we also took every single person from Nigeria, and for good measure everyone in hyper-crowded Japan too, we'd finally be up to China's 1.3 billion size.

Neeley, meanwhile, brought a data point to the conversation, from a 2012 Gallup survey:

About 13% of the world's adults -- or more than 640 million people -- say they would like to leave their country permanently. Roughly 150 million of them say they would like to move to the U.S. 

Of course there area more grounded ways to think about what a rationally generous immigration policy -- or asylum policy -- might look like, if the political will existed in the U.S. to open the door wider. But it's worth keeping in mind that there's still a lot of room on this continent, relatively speaking. Not that we'd want to take on anything approaching China's almost unfathomable governing challenges