Recent polling shows President Joe Biden's open-border immigration policy is now ranked as the No. 1 or 2 problem facing America -- in part because of the havoc in our large cities where the millions of migrants are now residing.

        Americans are a welcoming and generous people, but this policy of laying out a welcome mat to any and everyone who wants to come has stretched the bounds of our compassion to the breaking point.

        The vast majority of the current asylum-seekers are not criminals, drug runners or potential terrorists -- though some are. Most are simply coming here for the reason our parents and grandparents came: a better life and economic opportunity for themselves and their kids. They are not villains. They are the victims of Biden's inhumane and ruinous "let 'em in" border policy.

        It is going to take years -- maybe decades -- to figure out how we are going to deal with these 8 million or so migrants. Biden will not be president and likely won't even be alive as we work to undo the damage he's done to our immigration system.

        But there's an even larger casualty of this mindless policy. Biden has contaminated the historic public support for LEGAL immigration. And he has done so at the very moment in time when we need to continually increase legal visas.

        Right now, America issues roughly 2 million legal visas a year.

        Most economists agree that immigration at this level has been a source of strength for our economy as it allows us to import bright and productive and ambitious people from around the world. It's doubtful the U.S. would have reached the commanding heights of technology, medicine, the internet and now artificial intelligence without immigrant talent and brainpower -- the "brainiacs," as Larry Kudlow calls them.

        But it's also true that at no time in history have immigrants been more necessary than today. This is because of decades of low birth rates. The fertility rate for women of child-bearing age in the U.S. has fallen steadily from 3.3 to 1.78 over the past 70 years. A rate of 2.1 is the rate that keeps population size stable.

        Immigrants are contributors in many ways, but three stand out as particularly beneficial. First, most immigrants arrive between the ages of 18-35, so the child-rearing costs are borne by other nations and they arrive in their prime working years.

        Second, immigrants have higher labor force participation rates (67%) than most Americans (62%), and for the most part they are complimentary to rather than in competition with American workers. And third, immigrants have historically higher birth rates than Americans of the same age group.

        Without immigration it's going to be difficult to fill jobs, especially in industries like agriculture, construction, tech, home services and health care. It isn't just a cliche -- immigrants fill jobs that Americans often don't find desirable.

        We should gradually increase legal immigrant visas as soon as possible. We are about the only nation with the capacity to do this -- and to pick and choose who should come.

        Donald Trump recognized that you can't have public support for valuable legal immigrants before you close off the illegals.

        But this brings us back to Biden's planned chaos border policy. His policy is hurting everyone: the migrants who are coming illegally, the immigrants who are waiting their turn to come, and the American economy by denying our employers the immigrant workers they need. Biden keeps saying we need a "comprehensive solution" -- including an amnesty that few Americans will support today given the waves of illegals he's allowed in.

        There's no president in American history who has undermined our valuable legacy of immigration more than Joe Biden. Maybe he's the one who should be deported.

        Stephen Moore is chief economist at FreedomWorks and a senior fellow at the Heritage Foundation. His latest book is "Govzilla: How the Relentless Growth of Government Is Devouring Our Economy."