Money flows in and out of the U.S. like water, without (significant) restrictions, yet the movement of labor is strongly restricted.

Which way is it that "movement of labor is strongly restricted" in the US, ya think -- out of the country, or _into_ it? (You see any "ENS" rangers patrolling the Rio Grande, trying to keep the gringos IN?!? :-)


You can't unilaterally "restrict the [international] flow of money", either; t'would take international regulations.

And in *that* context, yes, you COULD make sure to "allow unfettered immigration to ANY country in the world".