Within recent memory, the neighborhoods north of downtown Portland, Ore., were among the most segregated in the Pacific Northwest. By 1970, violence and discrimination helped create large areas where African Americans made up as much as 84 percent of the population.

As of 2010, however, those same neighborhoods were no more than about 30 percent black — a change that reflects Portland’s current place as one of the least segregated cities in the country.

Since “most segregated” is an award most places aren’t eager to win, you might think local media would be celebrating. But Denis Theriault, writing for the Portland Mercury, described the changes as “sobering” and lamented the “futility of even trying to reverse it” — that is, of resegregating Portland’s African Americans.

That’s not because he’s a segregationist. It’s because he considered integration a form of gentrification.

That two of the highest priorities of liberal city-dwellers – preventing gentrification and fighting segregation – aren’t necessarily compatible with each other has become one of the most important, yet underacknowledged, tensions in the roiling debates about the future of American cities.

I bristle at the notion that a prime way to improve life in African-American neighborhoods is to import whites

True, every once in a while someone uses this contradiction to jab at anti-gentrification activists. “Let’s face it,” John McWhorter wrote back in February, in response to Spike Lee’s rant about white hipsters moving into black neighborhoods in Brooklyn. “The reason there were black communities like that was because of segregation…. [N]o matter how beautiful they would look when shot lovingly in films like Lee’s, it would signify racial barriers…. When racial barriers come down, people mingle, cohabitate, mate.”

This is all true enough. Moreover, scholars like Northwestern University’s Mary Pattillo and New York University’s Patrick Sharkey have amassed evidence that severe segregation imposes serious disadvantages on African Americans and other nonwhites, affecting such things as social mobility, education and even personal health. One recent study even found that segregation holds back the economic growth of entire regions.

The bigger problem, though, may be less that some people aren’t sold on integration as the key to creating more equitable cities, but that those feelings rarely become an open part of the debate. Instead, we’ve hit an uneasy balance in which nearly everyone says they believe that segregation is terrible, regardless of what they’d think of, say, young whites moving into (and integrating) a Latino community. That isn’t necessarily healthier than allowing serious debates over the role of segregation in racial inequality.

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Obviously, the greatest opposition to integration, today as in the past, comes from whites who are hostile to the idea of living in a neighborhood with too many people of color, especially if the color is black.

But America also has a long tradition of people who have fought racism while remaining ambivalent about the importance of integration. For the most part, these people have tended to be African Americans (famous examples range from early 19th century writer David Walker, to James Baldwin, to, apparently, Spike Lee). But the basic ideas can apply to many “outsider” communities — you hear them in one form or another among everyone from gay men to Jews.

One of the most basic arguments is that clusters of people with similar backgrounds help maintain a sense of community. People who share traditions – whether that’s Shabbat or brunch – can participate in them more easily if they live near each other. Community can also be an important safety net: One of the most famous efforts at desegregation, the Moving To Opportunity initiative of the 1990s, found that many public housing residents who were relocated to suburban areas lost access to child care, transportation or other informal services that close-knit friends or family had provided in their old neighborhoods.

While this argument applies to many different kinds of communities, it can be particularly powerful for racial minorities. In part, that’s because most American cities are so segregated that it can be difficult to balance community and isolation. While a Jewish person, say, may be able to find a part of town where Jews make up enough of the residents to create a strong community, but not so many that the area feels isolated from other kinds of people, the same is not necessarily true for Latinos, or especially for blacks. So while studies suggest that the average African American might like to live in a neighborhood that’s about half black, they’re unlikely to find that kind of middle ground.

There’s also the issue of safety. In a country where racism remains rampant, moving to an area where whites are a large majority may increase your odds of being a target of anything from petty humiliations at a convenience store to a catastrophic encounter with a frightened, and armed, neighbor. As one woman wrote to me after I published a piece on Chicago’s black middle class:

Personally, despite the great amenities the [whiter] North Side has to offer, I am very apprehensive about living there because of higher rent and racial tensions.

Others object to making integration a top priority on the grounds that doing so might send the message that there is something inherently wrong with black or Latino neighborhoods — and black or Latino people — beyond the battery of mortgage and retail redlining, disinvestment, disproportionate incarceration, and so on. In other words, racism.

As Naomi Davis, who runs an economic development organization on Chicago’s South Side, told me: “I bristle at the notion that a prime way to improve life in African American neighborhoods is to import whites.” For her, and many others, the solution is making sure that black people have their fair share of economic and political power, no matter where they live.

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The point here is not that the integration skeptics are necessarily right. There are any number of strong arguments on the other side. For example, many people of all races have fought for desegregation in schools on the grounds that the only way to guarantee that a mostly-white country won’t shortchange black children’s schools is if they are also white children’s schools.

No, the point is that it should no longer be possible to ignore that this debate, and these tradeoffs, exist. The kind of cognitive dissonance that allows someone to decry segregation while they wish to “reverse” the process of integration makes it impossible to articulate a real vision for what a just city might look like. Those who would declare themselves firmly anti-gentrification need to grapple with whether they’re comfortable defending a racial geography born of discrimination and violence, or whether there’s some other answer. Those on the other side, like McWhorter, ought to acknowledge that there are legitimate reasons to be wary of a neighborhood’s changing ethnic makeup.

Finally, of course, anyone who would see gentrification as an opportunity for integration needs to make sure that’s actually what’s happening. The old Chicago quip about white flight — that integration is the time after the first black person has moved in and before the last white person has moved out — often applies, in reverse, to gentrifying neighborhoods.

But connecting the dots on gentrification and segregation is more than just a problem of intellectual consistency. When we talk about racial change in Brooklyn or Washington, D.C., without acknowledging the larger context – the fact that for every black or Hispanic neighborhood seeing an influx of whites, there are 10 more that are just as segregated as they were 30 years ago – we’re missing what remains the fundamental inequality of American cities. What to do about the power and resource inequalities that both created and are sustained by segregation remains the fundamental challenge.

There may be more than one answer, but first we have to acknowledge the question.