Texas businessman Jay Johnson-Castro is a self-described Border Ambassador. But the word “crusader” might seem more fitting.

His journey started in September 2006, when Congress passed the Secure Fence Act. Outraged, Johnson-Castro decided to walk the 205 miles from Laredo to Brownsville in protest. “It was spontaneous,” says Johnson-Castro, 61, who was joined on his solitary walk variously by curious stragglers, town residents and community groups. “It was the first time I did anything like that in my life–but I just didn’t know how else to vent.”

A longtime border resident, Johnson-Castro calls the fence an assault on a community that goes back centuries. “People don’t understand that the border isn’t a black line that goes down the Rio Grande,” says Johnson-Castro. “It’s a community on both sides of the river. To divide us is an insult, a violation of our border culture and friendship.”

That next month, the Mexican town of Acuna invited him to replicate the march south of the border in a 60-mile trek, with the mayor of the city at his side. Since then, Johnson-Castro has embarked on a series of similar marches, some as far away as San Diego.

This week to highlight resistance to the fence’s construction in advance of the March 4 primary, Johnson-Castro is continuing his journey–this time joined by a band of about a dozen–across the 60 miles from Brownsville to Mission.

The first day it was 97 degrees out, and the smell of skunk and diesel fuel was heavy in the air. But the band kept walking. The group plans to complete their march this Sunday.

“I grew up with the Iron Curtain being the symbol of what we detested,” says Johnson-Castro. “Now, half a generation later, my government has turned around and is building miles of iron curtain to divide our community? I couldn’t believe that my country would do such a thing.”

Sens. Clinton, Obama and McCain all voted for the Secure Fence Act in 2006.