At least for the moment, it is. Last May, the Pew Hispanic Center, in a study based on U.S. and Mexican statistics, reported that net migration from Mexico to this country had fallen to zero from 2005 to 2010.
Pew said 20,000 more people moved to Mexico from the United States than from there to here in those years. That's a vivid contrast with the years 1995 to 2000, when net inflow from Mexico was 2.2 million people.
Because there was net Mexican immigration until 2007, when the housing market collapsed and the Great Recession began, it seems clear that there was net outmigration from 2007 to 2010, and that likely has continued in 2011 and 2012.
There's a widespread assumption that Mexican migration will resume when the U.S. economy starts growing robustly again. But I think there's reason to doubt that will be the case.
Over the past few years, I have been working on a book, scheduled for publication next fall, on American migrations, internal and immigrant. What I've found is that over the years this country has been peopled in large part by surges of migration that have typically lasted just one or two generations.
Almost no one predicted that these surges of migration would occur, and almost no one predicted when they would end.
For example, when our immigration system was opened up in 1965, experts testified that we would not get many immigrants from Latin America or Asia. They assumed that immigrants would come mainly from Europe, as they had in the past.
Experts have also tended to assume that immigrants are motivated primarily by economic factors. And in the years starting in the 1980s, many people in Latin America and Asia, especially in Mexico, which has produced more than 60 percent of Latin American immigrants, saw opportunities to make a better living in this country.
But masses of people do not uproot themselves from familiar territory just to make marginal economic gains. They migrate to pursue dreams or escape nightmares.
Life in Mexico is not a nightmare for many these days. Beneath the headlines about killings in the drug wars, Mexico has become a predominantly middle-class country, as Jorge Castaneda notes in his recent book, "Manana Forever?" Its economy is growing faster than ours.
And the dreams that many Mexican immigrants pursued have been shattered.
You can see that if you look at the statistics on mortgage foreclosures, starting with the housing bust in 2007. More than half were in the four "sand states" -- California, Nevada, Arizona and Florida -- and within them, as the Pew Hispanic Center noted in a 2009 report, in areas with large numbers of Latino immigrants.
These were places where subprime mortgages were granted, with encouragement from Fannie Mae and Freddie Mac, to many Latinos unqualified by traditional credit standards.
These new homeowners, many of them construction workers, dreamed of gaining hundreds of thousands of dollars as housing prices inevitably rose. Instead, they collapsed. My estimate is that one-third of those foreclosed on in these years were Latinos. Their dreams turned into nightmares.
We can see further evidence in last month's Pew Research report on the recent decline in U.S. birthrates. The biggest drop was among Mexican-born women, from 455,000 births in 2007 to 346,000 in 2010.
That's a 24 percent decline, compared with only a 6 percent decline among U.S.-born women. It's comparable to the sharp decline in U.S. birthrates in the Depression years from 1929 to 1933.
Beneath the cold statistics on foreclosures and births is a human story, a story of people whose personal lives have been deeply affected by economic developments over which they had no control and of which they had no warning.
Those events have prompted many to resort to, in Mitt Romney's chilly words, "self-deportation." And their experiences are likely to have reverberations for many others who have learned of their plight.
Surges of migration that have shaped the country sometimes end abruptly. The surge of Southern blacks to Northern cities lasted from 1940 to 1965 -- one generation. The surge of Mexicans into the U.S. lasted from 1982 to 2007 -- one generation.
The northward surge of American blacks has never resumed. I don't think the northward surge of Mexicans will, either.