The Cooper River chapter of Indivisible, a national grassroots organization that opposes President Trump, had barely begun its inaugural meeting Monday when it split in two.

But the division arose for the best of reasons: So many people -- many of whom learned of the group through its Facebook page -- were trying to fit into a room at the Collingswood Library that organizers had to hold a simultaneous second session in the parking lot.

"I'm done being on the sidelines," Craig Strimel, a communications studies teacher at  Community College of Philadelphia, declared to the spirited parking lot contingent.

Inside, his Westmont neighbor, Alexis Chase, told a standing-room-only crowd that the new Indivisible chapter was a tool for making "impactful and lasting changes" in the wake of Trump's ascendance.

The movement emerged around the time of Trump's inauguration and has been praised by Rachel Maddow and other liberal luminaries. It's modeled on the strategies of the right-wing tea party groups that sprang up to oppose President Barack Obama early in his first term.

The Indivisible Guide, a sort of manifesto mashed up with a how-to manual, describes the group as the brainchild of "progressive congressional staffers" seeking to "share insider information" about how citizens can influence Congress to fight the Trump agenda.

"The election," said Strimel, "was a wake-up call."

"I was astounded to see the level of interest," said Gretchen Seibert, who, along with Strimel and Chase, helped organize the event. "It says to me that people are hungry for positive change." An educator, Seibert added that the variety of age groups in attendance suggests the movement will be sustainable.

While big, loud, occasionally confrontational but mostly peaceful street protests have become a hallmark of what's being called the Trump resistance, the Collingswood event attracted the sort of crowd you'd see at a suburban civic association meeting, or perhaps a neighborhood park cleanup.

The people inside and outside were mostly middle-aged and middle-class. Blue-collar folks, senior citizens, younger men and women, people of color and members of the LGBT community were represented as well.

And the agenda was mainstream, more about calling one's member of Congress than calling for a revolution.

Copies of the Indivisible Guide were distributed, and inside, small groups of people arranged their chairs in circles to discuss issues of their choosing.

Among them were civil rights, the environment, and (my favorite) "Trump's attempt to delegitimize the press."

Before and after the event, people said they wanted to do more than merely commiserate with like-minded people or complain.

"I'm looking for something meaningful," explained Denise Dunham, 61, a retired educator who lives in Merchantville.

Some said they had long been involved with liberal causes – "I was at People's Park in Berkeley, back in the day," said Collingswood resident Wendy Decou – while others were relative newcomers to grassroots movements.

The indoor meeting featured trays of cookies, sign-up sheets, and selfies, and was held in a room where shimmering snowflake decorations hung from the ceiling, an entertaining bit of irony, given the spread of snowflake as a derisive term for Trump opponents and other progressives.

But the conversations I overheard weren't jargon-filled fantasizing, but pragmatic exchanges about how best to interact with elected officials and get other people involved via social media or face to face.

And Mary Page, a stylish 65-year-old retired paralegal, belied the stereotype of snowflakes as fragile, ineffectual creatures still boo-hooing about having lost the election.

With a beaming smile, the Berlin Borough resident told me how she had engaged in an impromptu protest about Ivanka Trump's clothing line at the Bloomingdale's Outlet on Thursday in Center City.

She held up a garment that bore Ivanka's label and announced that it had been made in China, stunning other shoppers before putting it back on the rack and leaving the store.

Her modest bit of guerrilla theater was worth it, Page said, "if I reached one person."