Many on the political right favor a so called “strong leader” for a variety of reasons, one of which is to restrict immigration. This is a main reason behind the current popularity of Donald Trump in the Republican party. He’s claimed the immigration issue as his own by promising to enforce the borders and making wild claims about deporting millions of illegal immigrants.
What these right wingers should understand, however, is that in a truly libertarian society, there would likely be much less migration and basically none into localities that didn’t want it. What we have now, as others have pointed out, is forced immigration.
First off, if all property in a given territory was privately owned, then the property owners themselves would have to invite migrants onto their land. Otherwise, if they showed up they would simply be trespassing, and the locals could forcibly remove them. Instead what we have is a situation where the State directly owns a large amount of the land. The government owns the roads, the parks, the schools, among other things and they decide who can access them. They also claim property rights on much of what is nominally considered “private.” For example, you can’t discriminate against any person based on their language, religion, or country of origin when running a business or renting an apartment. So if the residents of a town don’t like the influx of foreigners that have recently showed up, there is very little they can do to maintain their cultural hegemony.
It’s also worth noting that the State directly subsidizes immigration. Immediately upon crossing an imaginary line separating Texas from Mexico, a person finds themselves entitled to free education for their children and free medical care at any of the local hospitals. Discrimination, that evil, evil word, is not allowed. A newly arrived foreigner may also be able to get some direct Welfare benefits depending on their specific circumstances. In a libertarian society, of course, the State wouldn’t have access to the tax funds necessary to pay for this. They would also lack the authority to force hospitals to treat anyone they didn’t want to or local school systems to educate people they didn’t want to.
There is one last thing that States do that leads to more migration of peoples. This is one that’s really going to be hard for “conservatives” to hear because it’s the one part of government they universally seem to love. That is WAR. Without a powerful State, there would not be trillions of dollars available to be used to bomb and destroy foreign countries. It should be fairly obvious that if you destabilize a place by blowing it up and killing a bunch of people, that the natives of that land will want to leave. And guess where they want to go? Rich, Western, predominantly (for now) white countries. The Bush/Obama wars of aggression against Iraq, Syria, Libya, and Afghanistan have opened the floodgates of millions of Asians and Africans trying to get into Europe. The decades long drug war has helped destabilize Mexico and contributed to millions of Hispanics entering the USA.
Can Trump stop the tide? No one could really know for sure, but I highly doubt it. The real way to lower immigration is to dismantle the State.