SAN JOSE — National teachers union leader Lily Eskelsen Garcia offered a prediction Friday about gun lobbyists and politicians who are indifferent to the carnage of gun violence.

“I’m not an ordained minister, I’m not a theologian, but these guys are going to hell,” the National Education Association’s vice president said during a panel discussion at the Netroots Nation convention of liberal online activists.

“We have to make those senators as frightened of us as they are of the gun lobby,” she said. “Shame on us if we give one inch to the gun lobby. They got where they are because they never give up. … Now the movement is us; we are the ones we were waiting for.”

She and other panelists in the “Not Another Newtown: Building a Movement to Prevent Gun Violence” discussion said activists have a key role to play but can’t do it alone. Rather, all citizens who want stricter gun controls must seize politicians’ attention with a barrage of complaints and a steadfast promise to deny campaign funding to any who won’t listen — just as the gun lobby does, they said.

The panel opened the second day of Netroots Nation, an annual gathering of almost 3,000 liberal online activists who will be networking and strategizing through Saturday night at the San Jose McEnery Convention Center. Moderated by Fox News contributor Jehmu Greene, panelists said a chance for meaningful national change remains, even after the Senate’s rejection in April of a bill to broaden background-check requirements.

State Senate President Pro Tem Darrell Steinberg, D-Sacramento, said California is leading the way with bills that would, among other things, ban all semi-automatic rifles with detachable magazines; ban magazines that hold more than 10 rounds of ammunition; and require background checks for ammunition purchases.

“The gun lobby has been very smart about figuring out every single loophole to negate the assault weapons ban. We’re sick of the loopholes, we’re sick of the cat and mouse games,” he said. “We need to distinguish between responsible gun ownership, gun ownership for sport … and the extreme — the use of rapid-fire weapons that have no purpose but to kill.”

Mark Glaze, executive director of Mayors Against Illegal Guns, said that with 75 percent of National Rifle Association members believing that all gun purchases should require background checks, “we’re ripe for change.”

MoveOn.org executive director Anna Galland praised the Netroots Nation crowd. “The grass-roots engagement and leadership here is so important,” she said, but only in that it can mobilize the masses. “We need to have a movement that is 10 times bigger, a hundred times bigger than we have now.”

American Federation of Teachers president Randi Weingarten said the movement should take a page from immigration and same-sex marriage advocates and present clear, touching stories of those who gain and lose from gun violence. “When people see faces and when they are impacted individually, it changes minds,” she said.

Glaze rejected the gun-lobby argument that violent movie and video-game images are a leading cause of gun violence; the United Kingdom watches the same films and plays the same games, yet has only a fraction of the gun crimes because it places stricter controls on guns, he said. But some panelists said leaning on filmmakers and game manufacturers to clean up their products should be part of the equation, too.

“We enhance our credibility” by embracing some gun-lobby suggestions while also pushing for gun control, Steinberg said, also citing the importance of expanded mental health screening and services. “We have to broaden our message and be consistent.”

Rep. Robin Kelly, D-Ill., acknowledged this discussion in such a liberal venue might have been like preaching to the choir. “But the choir needs practice,” she said. “The choir needs encouragement.”

Netroots Nation continues Saturday with highlights including a Q-and-A session with House Democratic Leader Nancy Pelosi, D-San Francisco.

Josh Richman covers politics. Contact him at 510-208-6428. Follow him at Twitter.com/josh_richman. Read the Political Blotter at IBAbuzz.com/politics.