At marches and protests, Jaime Martinez is often the guy behind the bullhorn, shouting the slogans that become an event’s chorus. “Sí se puede,” or the more rhythmic, “El pueblo unido, jamás será vencido.”

Indeed, if anyone believes in “Yes, we can,” or that, united, a people cannot be defeated, it’s Jaime Martinez.

The retired union organizer — and trumpeter in The Fabulous SunGlows — is best known for founding the nonprofit César E. Chávez Legacy and Educational Foundation.

Over the weekend, it celebrated its signature event, the 17th annual César E. Chávez March for Justice. About 500 people participated in remembrance of the late labor leader’s life.

Twenty years after his death, Martinez remains an anchor in a nationwide network keeping Chávez nonviolent struggle for social and economic justice alive.

In his white guayabera sporting the United Farm Worker’s eagle, this year fitting significantly looser, Martinez stood in the middle of Guadalupe Street, bullhorn in hand, addressing the crowd.

He marched alongside them, but this year a golf cart rode along ready to scoop him up if necessary. Former Mayor Henry Cisneros convinced him to hop on for the uphill climb over the Guadalupe Street bridge. “It was a touching moment,” Cisneros said.

At 66, Martinez’s age is not the problem. Cancer is.

Diagnosed seven years ago, Martinez underwent surgery in his saliva glands. More recently, the suspicious spots on his lung revealed cancer had returned.

He’s undergoing chemotherapy, and in a few weeks tests will show how successful treatment has been.

Others have stepped in to help run the foundation, but Martinez hasn’t exactly taken a back seat.

He often repeats stories of “César,” but this year sounded wistful. “He really changed my life,” he says.

Martinez also reflected on his mother, who died when he was 3, the grandparents who raised him, and the grandfather who took him to union meetings, shaping his life’s work.

Over the years, Martinez has done a fair amount of shaping, too, influencing activists who come from the real world. Their hands have picked fruit. They’ve worked as housekeepers. They’re DREAMers brought to the United States illegally as children and fighting for comprehensive immigration reform.

“Once you educate the students about la causa,” he says. “You can’t un-educate them.” That’s why it’s important to plant the seed, he adds, and let someone else water it.

If it wasn’t for Martinez, UFW President Arturo Rodriguez says, San Antonio might not have established a street named for Chávez today.

Martinez seems at once ready for accolades and not. His blood work has been good, and says, “I’m going to live to be 100.”

But there is also a bittersweet sound in Martinez’s voice about what is for all of us inevitable.

“The march will continue long after we’re gone,” he said.