Tomas Martinez shouts into a megaphone during an immigration reform...

Tomas Martinez shouts into a megaphone during an immigration reform rally at the Atlanta City Detention Center in Atlanta, Georgia, on Friday, Nov. 21, 2014. The rally was part of a national "Chant Down the Walls" day of protest, according to organizers. The night before, President Barack Obama announced he will use executive action to stop the deportation of millions of undocumented immigrants. Credit: EPA / Erik S. Lesser

What in the world is happening along the U.S.-Mexico border? Have illegal immigrants stopped coming? Or are they still crossing -- and in record numbers?

Perhaps the answer depends on the country of origin. It could be that the number of employment-seeking Mexican immigrant men is on the wane, while the number of refugees from Central America -- mainly women and children -- is going up. No matter what you may believe, there is a study, article or anecdote to support it.

Just don't expect whatever you find to impact the immigration debate one way or another. This is where most folks go wrong. They stake out their position -- whether it is to give legal status to the undocumented, or to deport every illegal immigrant -- find some material to back it up, and then claim a decisive victory.

For instance, the Pew Research Center recently found that more Mexicans are leaving the United States than are entering. The study determined that, from 2009 to 2014, slightly more than 1 million Mexicans left the U.S. and went home. During the same five-year span, a slightly smaller number -- 870,000 -- left Mexico for the United States.

So it seems Mexicans are on the move. They're migrating south. And we're not talking about those 6th-generation Mexican-Americans who are sarcastically threatening to return to their ancestral homeland if Donald Trump is elected president.

Among the reasons cited for this reverse migration: family reunification, a sluggish U.S. economy, and concerns that border enforcement is about to be strengthened, which would make it harder and more expensive to bring across family members.

Immigration reformers hope this finding will defuse some of the anti-immigrant hysteria on the right. After all, they reason, why build what Trump promises would be "a big, beautiful wall" to keep out Mexicans when so many of them have already left?

Meanwhile, Julia Preston of The New York Times recently filed a story from Mission, Texas, a few miles from the border, noting that -- in just the last few months -- the number of migrants crossing the Rio Grande illegally has risen. According to the article, since the beginning of October, apprehensions by the Border Patrol of migrant families in the Rio Grande Valley have increased by 150 percent over the same period last year, and the number of unaccompanied children caught by agents has more than doubled.

Not that these people are all that hard to catch, mind you. Central American refugees typically search out agents and practically jump into their arms, eager to start the paperwork to apply for asylum.

Still, Border Patrol agents say that the whole scene hearkens back to the migration last summer of more than 80,000 refugees from Central America across the border and into South Texas.

So, if there is indeed a lot of foot traffic along the border, in which direction is it headed?

It doesn't really matter. Migration between Mexico and the United States is cyclical. Individuals come and go, in ebbs and flows, depending on the pull of family and job opportunities. You can't predict it. And you certainly can't make policy from it. Just because people aren't crossing today doesn't mean they won't be crossing next month or next year.

Besides, whichever direction the foot traffic is headed, the immigration debate won't be impacted one way or another. After all, that debate isn't really about who crosses the border. It's about who is already here. Those are the people who Americans are most afraid of because they think immigrants that stick around threaten something more precious than a border -- namely, the language, culture and society that the native-born hold dear.

People like to hide behind sanitized rhetoric about how immigrants allegedly commit more than their share of crimes, or the need to keep out terrorists, or the rule of law.

Yet, the immigration debate is driven by plain ol' fear. Many Americans tremble at the thought of living in a country that is becoming less white and more ethnic, a place they no longer recognize. It's that kind of fear that inspired a reader to declare to me recently that Latino immigrants are no less dangerous than Muslim extremists because "Latinos can harm us in ways different from tossing a bomb."

Whatever is actually happening along the U.S.-Mexico border, that's the uncomfortable reality on this side of the line.

SUBSCRIBE

Unlimited Digital AccessOnly 25¢for 5 months

ACT NOWSALE ENDS SOON | CANCEL ANYTIME ONLINE