Acentury ago, the immigrants from across the Atlantic included settlers and sojourners. Along with the many folks looking to make a permanent home in the United States came those who had no intention to stay, and who would make some money and then go home. Between 1908 and 1915, about 7 million people arrived while about 2 million departed. About a quarter of all Italian immigrants, for example, eventually returned to Italy for good. They even had an affectionate nickname, “uccelli di passaggio,” birds of passage.

Today, we are much more rigid about immigrants. We divide newcomers into two categories: legal or illegal, good or bad. We hail them as Americans in the making, or brand them as aliens fit for deportation. That framework has contributed mightily to our broken immigration system and the long political paralysis over how to fix it. We don’t need more categories, but we need to change the way we think about categories. We need to look beyond strict definitions of legal and illegal. To start, we can recognize the new birds of passage, those living and thriving in the gray areas. We might then begin to solve our immigration challenges.

Crop pickers, violinists, construction workers, entrepreneurs, engineers, home health-care aides and particle physicists are among today’s birds of passage. They are energetic participants in a global economy driven by the flow of work, money and ideas. They prefer to come and go as opportunity calls them. They can manage to have a job in one place and a family in another.

With or without permission, they straddle laws, jurisdictions and identities with ease. We need them to imagine the United States as a place where they can be productive for a while without committing themselves to staying forever. We need them to feel that home can be both here and there and that they can belong to two nations honorably.

Imagine life with a radically different immigration policy: The Jamaican woman who came as a visitor and was looking after your aunt until she died could try living in Canada for a while. You could eventually ask her to come back to care for your mother. The Indian software developer could take some of his Silicon Valley earnings home to join friends in a little start-up, knowing that he could always work in California again. Or the Mexican laborer who busts his back on a Wisconsin dairy farm for wages that keep milk cheap would come and go as needed because he could decide which dairy to work for and a bi-national bank program was helping him save money to build a better life for his kids in Mexico.

Accommodating this new world of people in motion will require new attitudes on both sides of the immigration battle. Looking beyond the culture war logic of right or wrong means opening up the middle ground and understanding that managing immigration today requires multiple paths and multiple outcomes, including some that are not easy to accomplish legally in the existing system.

A new system that encourages both sojourners and settlers would not only help ensure that our society receives the human resources it will need in the future, it also could have an added benefit: Changing the rigid framework might help us resolve the status of the estimated 11 million unauthorized migrants who are our shared legacy of policy failures.

Currently, we do not do gray zones well. Hundreds of thousands of people slosh around in indeterminate status because they’re caught in bureaucratic limbo or because they have been granted temporary stays that are repeatedly extended. President Obama created a paler shade of gray this summer by exercising prosecutorial discretion not to deport some young people who were brought to this country illegally as children. But these are exceptions, not rules.

The basic mechanism for legal immigration today, apart from the special category of refugee, is the legal permanent resident visa, or green card. Most recipients are people sponsored by close relatives who live in the United States. As the name implies, this mechanism is designed for immigrants who are settling down. The visa can be revoked if the holder does not show “intent to remain” by not maintaining a U.S. address, going abroad to work full time or just traveling indefinitely. Legal residents are assumed to be on their way to becoming Americans, physically, culturally and legally. After five years of living here, they become eligible for citizenship and a chance to gain voting rights and full access to the social safety net.

This is a fine way to deal with people who arrive with deep connections to the country and who resolve to stay. That can and should be most immigrants. But this mechanism has two problems: The nation is not prepared to offer citizenship to every migrant who is offered a job. And not everyone who comes here wants to stay forever.

It may have once made sense to think of immigrants as sodbusters who were coming to settle empty spaces. But that antique reasoning does not apply when the country is looking at a long, steep race to remain competitive in the world economy, particularly not when innovation and entrepreneurship are supposed to be our comparative advantage. To succeed, we need modern birds of passage.

The challenges differ depending on whether you are looking at the high end of the skills spectrum, the information workers or at low-skilled laborers.

A frequent proposal for highly skilled workers comes with the slogan, “Staple a green card to the diploma.” That is supposed to ensure that a greater share of brainy international students remain in the United States after earning degrees in science and technology. But what if they are not ready for a long-term commitment? No one would suggest that investment capital or design processes need to reside permanently in one nation. Talent today yearns to be equally mobile. Rather than try to oblige smart young people from abroad to stay here, we should allow them to think of the United States as a place where they can always return, a place where they will spend part, not all, of their lives, one of several places where they can live and work and invest.

Temporary-worker programs are a conventional approach to meeting low-skilled labor needs without illegal immigration. That’s what President George W. Bush proposed in 2004, saying the government should “match willing foreign workers with willing American employers.” An immigrant comes to do a particular job for a limited period of time and then goes home. But such programs risk replacing one kind of rigidity with another. The relatively small programs currently in place don’t manage the matchmaking very well. Competing domestic workers need to be protected, as do the migrant workers, and the process must be nimble enough to meet labor market demand. Nobody really has pulled that off, and there is no reason to believe it can be done on a grand scale. Rather than trying to link specific migrants to specific jobs, different types of temporary work visas could be pegged to industries, to places or to time periods. You could get an engineering visa, not only a visa to work at Intel.

Both short-term visas and permanent residence need to be part of the mix, but they are not the whole answer. Another valuable tool is the provisional visa, which Australia uses as a kind of intermediary stage in which temporary immigrants spend several years before becoming eligible for permanent residency. The U.S. system practically obliges visitors to spend time here without authorization when they’ve married a citizen, gotten a job or done something else that qualifies them to stay legally.

We also could borrow from Europe and create long-term permission to reside for certain migrants that is contingent on simply being employed, not on having a specific job. And, legislation could loosen the definitions of permanent residency so that migrants could gain a lifetime right to live and work in the United States without having to be here (and pay taxes here) more or less continuously.

The idea that newcomers are either saints or sinners is not written indelibly either in our hearts or in our laws. As the size of the unauthorized population has grown over the past 20 years or so, the political response has dictated seeing immigration policy through the stark lens of law enforcement: Whom do we lock up, kick out, fence off? Prominent politicians of both parties, including both presidential candidates, have engaged in macho one-upmanship when it comes to immigration. So, President Obama broke records for deportations. Mitt Romney, meanwhile, vows to break records for border security.

Breaking out of the either/or mentality opens up many avenues for managing future immigration. It could also help break the stalemate over the current population of unauthorized migrants. No election result will produce a Congress that offers a path to citizenship for everybody, but there is no support for total deportation, either.

If we accept that there are spaces between legal and illegal, then options multiply.

Citizenship could be an eventual outcome for most, not all, people here illegally, but everyone would get some kind of papers, and we can engineer a way for people to work their way from one status to another. The newly arrived and least attached could be granted status for a limited time and receive help with returning to their home countries. Others might be offered life-long privileges to live and work here, but not citizenship. We’d give the fullest welcome to those with homes, children or long time jobs.

By insisting that immigrants are either Americans or aliens, we make it harder for some good folks to come and we oblige others to stay for the wrong reasons. Worse, we ensure that there will always be people living among us who are outside the law and that is not good for them or us.

Roberto Suro is a professor of public policy and director of the Tomás Rivera Policy Institute at the University of Southern California. He is a coauthor of “Writing Immigration: Scholars and Journalists in Dialogue.”

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