In recent weeks, a group calling itself ProjectUSA has caused quite a stir in New York City by placing anti-immigration billboards in Queens.

Bearing messages such as, "Over 80% of Americans support very little or no more immigration. Is anyone listening to us?" these billboards have outraged immigration defenders, who proudly point to the city's tradition of accepting generations of immigrants from all over the world.

What's significant about the controversy isn't ProjectUSA's message of immigration restriction. That's hardly a new idea. What should command our attention is the skillful way the group has presented its message as reformist rather than reactionary. 

Ever since the earliest days of the 17th century, at least some Americans have called for restricting immigration. In so doing, they've relied upon two tested formulas, both of which are apparent in the ProjectUSA campaign. 

First, opponents make a crucial distinction between present-day immigration and immigration of the past. ProjectUSA's Web site is emphatic on this point. This is essential because most Americans can point to an immigrant ancestor.  Past immigration was different, so the myth goes, because the immigrants were different ( i.e., from Europe) and willing to Americanize (as though there was much choice). America was a different place, the myth continues, despite historical evidence to the contrary, with more jobs and no welfare.  Thus, among the 3 million who annually throng to the Statue of Liberty and Ellis Island to celebrate their proud immigrant past, we find many leery, if not downright hostile, to the idea of continued immigration.

One of the surest signs of Americanization is the willingness of immigrants or their children to support  Immigration restriction.  Sociologists call it the 

treehouse effect — the willingness to deny others entry by pulling up the ladder once safely inside.

Second, while there has never been a shortage of people willing to condemn immigration in nakedly racist terms, the most effective groups have always dressed up their bigotry in high-minded concern for the common good.  For example, in the 1840s nativists cast their attacks on Irish Catholics in terms of civic duty — loyalty to the Pope in Rome and priests here rendered those immigrants incapable of exercising the duties of republican citizenship. In the 1880s, Congress passed the Chinese Exclusion Act to protect American workers from cheap "coolie labor." At the turn of the century, opponents of immigrants turned to the "science" of eugenics to shroud their virulent racism.

ProjectUSA's billboard campaign is simply the latest version of this tradition. The group carefully avoids casting its opposition to immigration in terms of race or culture. Instead, it cloaks its bigotry in allegedly high-minded concern over population growth, environmental damage or urban sprawl.

Craig Nelsen, the group's founder, goes to great lengths to convince his critics that "it's not about skin color. It's about numbers." Such assurances ring about as sincere as the line, "It's not about the money."

Whatever we decide about the future of immigration in America, we would do well to avoid both convenient myths and disingenuous "activists."