Immigration is indeed a problem; all Americans agree on that. The right is largely opposed to any immigration, and the left understands that the tolerance of the American people on this issue is limited.

Every county has a right to control its borders, and even its culture and heritage from wholesale dilution by migrants from the global south, and yet we are all one race. Should borders matter?

Furthermore, our laws offer adjudication of asylum claims to anyone who presents themself at the border. How do we resolve this conflict between our history of welcoming immigrants and the reality of overpopulation, and threats of cultural suicide?

I have bad news – population is growing fastest in the developing world, and much of that is in the global south. Climate change threatens to make much of that area uninhabitable. The inescapable result is that there will be ever-increasing pressure on northern developed countries to control their borders against massive movements of peoples.

Now the right knows how to deal with this: Stop immigration into the U.S. altogether. The left, however, is in a quandary. Traditionally supportive of immigration as a matter of principle and also to supply needed labor, it has to decide how to respond in a way that gives it political relevancy.

I would argue that the right (read Republican) has been more effective at electoral politics in this country, while the left or center-left (Democrats and independents) has been more effective at governing. That is, solving societal problems.

But both are going to have to meet the challenge of massive migration head-on. Progressives, in particular, in order to remain relevant, have to accept the reality that we are no longer the nation that can say, “Give me your tired, your poor, your huddled masses.”

There was such a time, but no longer; probably never again. Sad, but true.

It is especially crucial that the left look at the future and respond in a way that keeps it relevant, and this election represents the beginning of that response.

Robert Purrington is a theoretical physicist, retired from Tulane University. He divides his time between Durango and New Orleans.