I hear that a lot of people want to migrate to...Finland. I'm pretty sure it's not because they like Finland's climate, or scenery. I don't think it's got anything to do with the physical geography of Finland. I think that they want to move to Finland because they like Finland's political, legal, and social institutions, and all the good things those institutions bring. They want to live somewhere that is ruled by Finns.
There are two ways to satisfy that desire.
1. We can move the people who want to live there to the country they want to live in.
2. We can move the country they want to live in to the people who want to live there.
If nobody cared about physical geography, those two solutions would be exactly the same. But if people do care about physical geography, and want to move to Finland despite not liking its climate, the second solution would be better.
Letting people migrate across borders is not enough; we need to let land migrate across borders too.
So instead of moving the people across the borders, we should move the borders across the people. What people are really voting for, when they vote with their feet, is imperialism. They want to be ruled by foreigners.
Imperialism has a bad name only because, in the past, countries moved to places where the people living there didn't want to be ruled by foreigners. But that is not what we are talking about here. New imperialism would be different and much better than the old, precisely because we are talking about moving countries to places where the people living there do want to be ruled by foreigners.
There is of course a practical difficulty, because unanimity is rare in practice. A minority of people living in any given geographical area might not want a bunch of foreigners coming in and taking over. But that same argument applies to both of the two ways of resolving the migration problem. And it can be resolved more easily in the second way. If (say) half of Nigerians would prefer to live in Finland, then Finland should take over half of what is currently Nigeria (preferably that half with the highest density of people who prefer to live in Finland, to reduce moving costs), and let the disaffected minority move to the remainder of Nigeria.
Instead of thinking about borders as geographically fixed, we should think of borders as geographically fluid markers of boundaries between rulers, moving back and forth across the land according to the ebb and flow of preferences of who wants to live under which ruler.
Obviously I am just using Finland as an example in this thought-experiment. The real world Finland is much too small a country to take over half of Nigeria. And my guess is that nearly all the people who want to move to Finland would be equally happy to move to Sweden or Denmark or even Germany, France, or the UK. Rather than individual European countries doing it alone, like under old imperialism, new imperialism should be a pan-European project.
Fortunately, Europe already has in place the institutional structure that could implement renewed imperialism, namely the EU itself. But perhaps the US and Canada (as countries founded by European immigrants, to which many people want to emigrate) could join the EU in this pan-European project. And there's no reason, of course, that renewed imperialism should be restricted to European countries. Perhaps many people want to live under Japanese rule too, for example.
I fully recognise that many readers will find my proposal for a renewed imperialism absurd. That's because you think of the current location of borders as somehow sacred. You might even want to start a war to protect the existing location of your borders if a bunch of foreigners tries to cross some arbitrary line on the map, and move that line to somewhere else. But unfortunately, the attitudes behind those sentiments are really just based on an irrational fear of foreigners. Economic theory, and econometric studies, clearly show that competition between countries for people and land will maximise economic welfare just like competition between firms for customers. Customer loyalty to a particular brand reduces competition, and leads to a less efficient allocation of resources.
This policy proposal would make an improvement to global human welfare that is far bigger than any other policy (like global free trade, for example). If Europe moved to the poor countries, there is no reason why the people currently living in those poor countries could not have European levels of GDP per capita and standards of living.
And remember, for every desperate migrant you see voting with his feet to live under European rule, there must be hundreds more equally desperate people who would like to vote the same way too, but who can't move so easily.