Why not open borders?

“The border!” was one of the chants heard during the president’s State of the Union speech. The condition of the US border and border enforcement are hot button issues currently. One can find a whole host of articles and studies extolling the benefits and virtues of allowing immigration, legal or not, and defending the numerous “sanctuary cities” in the US (Canada and Europe as well).

However, Democratic politicians, such as Cory Booker, have claimed that the Democratic Party does not advocate for open borders and resent the GOP implication that the US borders are virtually open and intentionally so. I have to point out here that the term “open border” itself is pretty vague. If one looks it up, the types of national borders are numerous and varied. Admittedly, it is not simply a binary choice of open/closed borders. But… to those who oppose highly regulated immigration, are for policies such as amnesty and sanctuary cities, but, like Cory Booker, insist they are not advocating for open borders, my question is:

Why not have open borders?

I bet the Native American's wished they had closed borders. Following Christopher Columbus' arrival in North America in 1492, violence and disease killed 90% of the indigenous population — nearly 55 million people.

Correct. Most of history is a cautionary tale for the more than sheeps.

The English knew the most effective way to conquer a nation is through a vagina. :)

Anyone here who fits this description?

I'll go for open boarders as long as the countries the people  come from  assume our entire national debt and pay for all welfare and govt assistance programs.

After thinking about your point (which I will quote) is below:

When automation comes, everyone is going to be unemployed.  But if society assumes this, we wouldn’t go to college or even try in school (because what’s the point of studying for jobs machines are going to take)?  If it is a bad idea to slack off in school based on the idea try at machines are going to take our jobs, we should plan for things at least until automation comes as if automation isn’t going to come.

When automation comes, the wealth generated from automation would spread out to the world (because the internet is global) so we wouldn’t have immigration basically since from the perspective of migrants, why move to a completely different area if you are rich in your home country due to automation making everything free?

But for the time being, we live in a pre automation time, so we should have a pre automation immigration policy (open borders for blue counties).