Presidential candidate Beto O'Rourke stops at San Quentin, Oakland

Presidential candidate Beto O'Rourke, on a campaign swing through the Bay Area, is defiant about confiscating assault weapons. 

Outside San Quentin State Prison, and later at a San Anselmo fundraiser, the Democrat from Texas said his position is the right one, and he believes most Americans agree. 

"I have this opportunity to do the right thing and say the right thing, while we still have time," said O'Rourke, after emerging from a two-hour visit to the prison. 

Wednesday morning, tweeting on gun reform, President Trump slammed O'Rourke with "Dummy Beto made it much harder to make a deal". 

But the former Texas Congressman had a firm retort an hour later: "To be clear, we will buy back every single assault weapon.... that's what the American people want- and deserve."

In Marin, O'Rourke shrugged off the Twitter insult, saying he "could care less" what the president thinks. 

He did take a swipe at his rivals, who support a ban on assault weapon sales, but are generally more cautious about seizing them from existing owners. 

"Some Democrats who are running scared on this issue are running away from those they represent," said O'Rourke. "I'm sick and tired of people in positions of power being scared and afraid and complicit in the violence and bloodshed."

During his prison tour, O'Rourke met with staff and inmates to talk about rehabilitation and race. 

"I'm thinking about  a prison population of 2.3 million in this country, largest on the planet, disproportionately  comprised of color," he told reporters afterward.

Off camera, a prison chaplain who was in the chapel described O'Rourke listening to more than a dozen inmates describe their crimes, regrets, and  education achieved while incarcerated. 

"That benefits the individual, it's better for the taxpayer, and better for society," said O'Rourke.

He noted his youthful arrests, for DUI and trespassing, didn't define him or hold him back. 

"That has a lot to do with my race, and luck, and circumstance and privilege," he said. 

In Marin County, a place of privilege, those attending O'Rourke's fundraiser at a private home were charged a sliding scale and many volunteers were invited so the candidate could thank them personally. 

Some have been working the phones to turn districts blue across the country; and some volunteered on O'Rourke's Senate race as well. 

About 80 guests cheered his arrival, and listened to his remarks on a range of topics. 

"He really reminds me of Bobby Kennedy Jr.," said event co-host Megan Matson, impressed by O'Rourke's energy and ideals. 

Although he is polling in the 1-2% range, Matson insisted she is not discouraged this early in the race. 

"There is huge room for change as people actually start paying attention," said Matson. "I've been going up and down the street putting up signs and I've had people say, 'what's Beto?'""   

As O'Rourke lingered, an hour longer than expected, neighbors not on the guest list listened from the sidewalk, peering over a fence. 

One neighbor said she was intrigued by how O'Rourke, after the El Paso mass shooting, has made gun reform his signature issue.  

"That was putting one foot in the water which he did, and made a big splash, but now more dialogue has to happen," said Elaine Meholick.

On Thursday morning, O'Rourke will participate in a round-table discussion at "Blunts and Moore" cannabis dispensary to discuss his proposal on the war on drugs. He's already floated a sweeping plan to legalize marijuana and grant clemency to those serving sentences for marijuana possession.