[notworthmyjob]

It's worth remembering that the USA had heavily regulated borders between 1921 and 1965 and it's impossible to know how things would have turned out if they had stayed open. More incidentally, starting during WWI, speaking German in the USA was not encouraged, to say the least.

Furthermore, I would argue that the modern US government was _invented_ during the era of closed borders. Consider the New Deal's various incarnations, Social Security, robust regulation of business, the Wagner Act, etc. Continuing on to post war managerialism. Libertarians may want Guilded Age business policy and immigration policy, but a lot of people just want to cherry pick the immigration policy.