Now, the two men are at ideological odds: Delao encourages young people to consider the path he chose, while Paredes tries to spare them from making the same choice.
On Tuesday, dozens of Oakland High School students watched with interest as the two men debated the tactics of military recruiters and the risks and benefits of joining the service.
"Right now, tens of thousands of people, just like you, have come back from the Iraq and Afghanistan conflicts with injuries that are going to affect them for the rest of their lives,'" said Paredes, who in 2005 was convicted in a court-martial after refusing to board a ship to Iraq because he opposed the war.
"Each individual who joins the military has their own story," Delao countered.
The debate was timely. It took place just hours before the Berkeley City Council was scheduled to reconsider its controversial resolution against the presence of military recruiters in the city. The event was part of a week-long campaign sponsored by the Oakland teachers union, and included similar forums at Oakland Technical High School, Fremont Federation and Laney College.
Paredes warned students of the physical and psychological trauma they might experience if they joined the military and were deployed. He also said the "skills" acquired in the service often aren't useful in the civilian world, contrary to what recruiters might say.
While Delao didn't deny the risks involved in combat, he stressed that every person who enlists has a different experience. Some thrive, while others don't, he said.
Delao said the service offers young people the discipline and tuition assistance they might need in order to be successful in college, or in the career of their choice.
"Our intent is not to come and hoax you to get you to join," he said.
Jennifer Garcia, 17, said she had an open mind about the military, but that she was very conscious of the dangers of enlisting, particularly in wartime. It's important to hear both sides of the story, she said, because some of her classmates are only thinking about the money they would make in the service, or the college tuition help they would receive. She, too, once thought about joining for that reason, she said.
"College is expensive nowadays," Garcia said. "I don't think there's enough information on ways you can get money if you need it."
Quinton Pierce, 18, is a member of the Junior Reserve Officers' Training Corps, a U.S. military-run leadership program for high school students. He said his brother has returned from Iraq "perfectly fine," and that he is thinking about enlisting after he graduates from Oakland High School.
Pierce said recruiters sometimes set up an obstacle or climbing wall course at the school, but that they don't bother students on campus. After the debate during which a teacher in the audience started arguing with a military officer Pierce said he didn't appreciate the anti-military sentiment he sensed from the crowd.
"They're trying to be followers," he said. "They're trying to copy off Berkeley."