If they don't want to raise quotas then they don't really want legal immigrants. They just want to keep everyone out.
The idea of closed borders, immigration caps, etc is relatively modern and driven more by the fact that social entitlement programs cost money than a fear of dangerous people coming here.
Entitlement programs only work if we can secure our borders. If we can't secure our borders it seems to be clear that we can't have the entitlement programs.
Unless you were coming off a boat from Africa. Lets not forget that slavery defined a large section of American history.
That's separate from the core topic here though. The slave trade and all the problems that go along with it do not change the fact that our borders were open for a majority of our history.
https://www.nytimes.com/2017/08/02/us/politics/trump-immigra...