1) welfare state -- "bad" immigrants impose higher costs now. 2) technology -- bad immigrants (in the form of terrorists) impose potentially existential costs

1) welfare state -- "bad" immigrants impose higher costs now. 2) technology -- bad immigrants (in the form of terrorists) impose potentially existential costs now. Also, in that period immigration was inherently racist, which I'd absolutely like to change. ("Chinese exclusion act", etc) Economics have also changed; costs of migration into the US are far lower than before, and we are far richer than we were then, so it changed who would immigrate. I'd expect a remote, expensive to reach place with endless land and a shortage of labor to have different immigration policies than a rich country next to a poor country a short walk away.