Too late for the wall against Mexico?

It may already be too late to build a wall against Mexico.

Michael Barone, in his fine book Shaping Our Nation, talks about the cycles of immigration to the United States. Immigration tends to come from countries that are just shy of middle income. They're not so poor that residents can not afford to leave, but not yet so rich that they stay to work in domestic industries. For much of the 20th Century, Mexico fit that bill. The great wave of migrants from Mexico came after the Second World War and continued up to the Great Recession in 2008.

During the recession, though, Mexican migration was negative. That is, there were more returnees than new migrants. This could just be an effect of the recession, and the Mexican migration might resume. However, Barone makes me think that the main era of Mexican migration to the United States is over. The Mexican economy, despite the violence and corruption of some parts of it, is now heading into the middle income of world economies. Moreover, the Mexican birthrate has declined to replacement levels. The pressure of young people to find jobs has diminished.

It might be a great irony of the Trump years that we make a "yuge" effort to build a big wall against Mexico at the very time when it is no longer relevant.