He is extolling free trade pacts and his commitment to fighting drug traffickers, but when the topic of immigration arises - as it inevitably will in Mexico - McCain's Straight Talk Express will hit a dangerous fork in the road.
He wants to project a compassionate and friendly image to both his Mexican hosts and Latino voters in swing states who will be voting in unprecedented numbers this fall. On the other hand, he must telegraph his eagerness to "secure" the border and crack down on immigrant "lawbreakers" to rally the anti-immigrant base of his own party.
This won't be easy. But an even more fundamental fault line runs through McCain's position and right across party lines: The very type of free trade pacts McCain is advocating are linked at their roots to the economic forces that accelerate undocumented immigration to the point of breaking our immigration system.
The North American Free Trade Agreement, the modern model for U.S. trade policy, is the prime example.
During the fierce 1993 fight over its adoption, treaty promoters assured the U.S. and Mexican publics that expanded trade would slow immigration by increasing economic opportunity in Mexico. Sadly, 14 years of NAFTA have shown the opposite: Unauthorized migration from Mexico has doubled.
Most of the estimated 12 million immigrants living and working without papers in the United States today are Mexican. Economic displacement and a bleak opportunity landscape in Mexico compel approximately half a million more souls to move to the United States every year.
McCain and other NAFTA boosters who have masqueraded as champions of pragmatic immigration reform are reluctant to acknowledge inconvenient facts, such as the value of the Mexican minimum wage dropping 23 percent in NAFTA's first decade. Nineteen million more Mexicans live in poverty now than 20 years ago.
The NAFTA years have produced unprecedented wealth for a tiny elite and disaster for the quarter of Mexico's population who cannot even afford basic foods. In 2008, hunger is growing because Mexico is at the forefront of developing nations hit by rising food prices.
The immigration issue will test the creativity of any incoming administration, be it McCain or Obama. They will inherit an intensely emotional debate badly in need of bold vision and common sense.
Genuine reform will not come from spending more on security tactics that ignore the powerful market forces driving immigrants north across the 1,969 miles of border Mexico shares with the United States. And it will require looking beyond free trade panaceas.
This is especially challenging when American workers are in a bad stretch. The opening for the candidates is to explain that both nations have a stake in developing economic opportunities in Mexico capable of sustaining communities and keeping families home.
Our leaders must attend to the legitimate concerns of American workers, but never by portraying displaced Mexicans and Central Americans in our labor market as a threat to our well-being.
I hope John McCain gets a chance to visit the devastated Mexican countryside for a firsthand look at the gap between what NAFTA promised and what it delivered. It might cool his ardor for ill-considered trade policies and let him get back onboard his straight talk express.