PHILADELPHIA — It was Friday, and Ann Mintz could not stop writing.

“Dear Sec’y Azar, This is a shocking shameful chapter in our history,” she wrote on a postcard to the secretary of the Department of Health and Human Services.

“Dear A.G. Sessions, I write as the daughter of a Holocaust survivor,” began another postcard adorned with an American flag to the U.S. Attorney General.

“Dear Sec’y Nielsen, Families belong together,” she scribbled to the secretary of the Department of Homeland Security after a week jam-packed with news about controversial health-care proposals, legal investigations into President Trump’s associates and separated migrant families struggling to reunite.

Every week since Trump’s inauguration, this has been Mintz’s Friday routine: meeting up with her friends to oppose his presidency and thwart his agenda — by penning a thick stack of postcards.

In an era of hashtags and viral videos, it is perhaps an unlikely, old-school medium. But for tens of thousands of resistance-minded liberals in the age of Trump, the humble postcard has become a weapon of choice.

“It’s a way to stay sane, to not be overwhelmed by the unremitting storm we’re living in,” said Mintz, 71, taking a break to stretch her hands at a recent postcard meetup. The past few weeks have been especially exhausting as her postcards have bounced among crises — Supreme Court Justice Brett M. Kavanaugh’s confirmation hearings, new government crackdowns on undocumented immigrants, and the mass shooting at a Pittsburgh synagogue.

“I don’t have carpal tunnel yet, but I haven’t handwritten so many things since grade school,” she said.

Across the country, clubs devoted to postcard writing have popped up in liberal bastions such as Boston and California and in conservative strongholds in rural Alabama and Texas. Many — including Mintz’s group — write weekly to their local representatives, federal judges, gun shop owners, immigration lawyers and federal agencies. Others write to voters in swing districts, personally begging them to hold the Trump administration accountable via upcoming midterm elections.

Some groups meet at bars, coffee shops and pizza joints. Others throw writing parties in each others’ homes. In Chicago, 15 clubs have banded together to form a competitive postcard-writing league, with a running scoreboard that tracks teams with the most postcards mailed.

A new national umbrella group on Facebook — Postcards for America — now has more than 9,700 members and 16 state chapters. A second group, called Postcards to Voters, emerged last year and now has more than 25,000 volunteers who have sent roughly 3 million handwritten postcards targeting voters in districts where there’s a chance to flip Republican-held offices.

Etsy shops have rushed to cater to the groups with progressive-themed stationery. Liberal-leaning graphic artists have coordinated efforts to offer free printable designs online.

Mintz — a retired museum director who is a member of three postcard clubs in her Philadelphia neighborhood — said she realizes that to some their mailings might appear naive, the self-indulgent overreaction of liberal snowflakes.

“It may seem silly to think postcards can do anything,” she said. “And, yes, maybe one postcard doesn ’t. But a couple hundred postcards? A thousand? Tens of thousands? That could move the needle.”

A nod to the past

Sending letters as a political act has deep roots in American history.

A deluge of letters was said to have helped persuade George Washington to become the nation’s first president. During the Civil War, soldiers and their families wrote to President Abraham Lincoln. Martin Luther King Jr. famously wrote his own letter of protest from Birmingham’s jail. Today, the U.S. Senate continues to receive more than 11 million pieces of mail a year.

But the rise of postcard writing clubs as a collective form of activism — an act of solidarity and group therapy of sorts — has only recently gained widespread traction amid the Trump presidency.

Across several cities, many groups say they started meeting up at first just to vent. Others trace their origins to last year’s Women’s March and resistance groups such as Indivisible.

Their rapid growth has been fueled by a marriage of old-school penmanship and modern-day tech and social media. Many coordinate on Twitter and Facebook.

To distribute the addresses of thousands of Democratic-leaning voters to writers every week, the leaders of the Postcards to Voters group created an auto-reply text bot (named Abby) that now farms out assignments by text message. Organizers set up an elaborate online system to screen and coach newcomers, and they created an internal audit that uses fake addresses to ensure that the 56,000 postcards sent out weekly make it into the mail system.

This summer, the group’s leader, Tony McMullin, 52, quit his high-paying job managing IT for a regional bank to manage the surge of volunteers signing up ahead of the midterm elections.

In the past year, the group has written postcards for more than 120 races, including more than 347,000 messages it sent to Alabama regarding the U.S. Senate race that resulted in Democrat Doug Jones’s defeating Republican Roy Moore. The group also has focused on smaller elections, such as for county sheriff in Virginia and a rural circuit clerk in Oktibbeha County, Miss.

Eileen Higgins said she kept stumbling across the group’s postcards in Florida while canvassing this summer as a first-time candidate for a Miami-Dade County commissioner seat previously held by a Republican for 20 years.

“I can’t say this one thing is what won it for us,” Higgins said. “But I can tell you nobody said a word about any direct mailers we sent or phone calls. And yet so many people would run inside their houses to show me these craftsy, little cards they got from people around the country.”

Election as impetus

For Mintz, the retired museum director in Philadelphia, the urge to write began shortly after the 2016 election.

When Trump announced his travel ban on people from several Muslim-majority countries, Mintz said she couldn’t stop thinking about her father — a Russian Jewish refu­gee whose entire family was killed in the Holocaust. Mintz started scrutinizing people she met on the street with suspicion, trying to imagine which of them may have voted for Trump. She lay in bed unable to sleep, she lost 30 pounds and started seeing a therapist for anxiety.

It wasn’t until the Women’s March in January 2017 that Mintz felt for the first time that she wasn’t alone in her despair. Soon after, a friend told her about women in the neighborhood who had started writing postcards together.

Their messages in the beginning tended to be long, angry screeds — reacting to the president’s latest tweet or policy. But over time their messages have become shorter — constrained both by hand cramps and strategic thinking.

“You realize no one is going to read beyond one or two lines,” Mintz said.

The women — mostly white, retired emptynesters — call their group the Persistent Postcarders, taking their name from the “Nevertheless, she persisted” comment Senate Majority Leader Mitch McConnell (R-Ky.) made last year while trying to silence Sen. Elizabeth Warren (D-Mass.).

On a recent Friday, as they gathered at a home in northwest Philadelphia, many of them arrived with urgent targets in mind.

“Did you see Jeff Sessions’s announcement for a ‘religious liberty task force?’ It’s crazy,” Mintz said.

Other women around the thick oak table quickly began scribbling.

“I honestly don’t know what to say to Kirstjen Nielsen anymore on the family separation thing,” said Tamar Jacobson, 69, an early-childhood education professor at Rider University in New Jersey.

“How about just, ‘Shame!’ ” Mintz replied gleefully.

The women have tried in recent months to write more thank-you notes than angry, critical ones.

“You get burnt out on outrage after a while,” explained Betsy Teutsch, 65, a graphic designer. “And gratitude sometimes has a greater effect than yelling at people.”

The one person they seldom write any longer is Trump.

“It just seems like a waste of time,” said Helen Feinberg, 72, a grandmother. The last postcard she sent to the White House was a few months ago after Trump called a black congresswoman “low IQ.” Furious, Feinberg scrawled a succinct message on a blank card: “Mr. Trump, Shut your filthy mouth.”

Who replies?

The group never got a response from the White House, but they have heard back from many others. Attorneys general in Washington, Hawaii and Pennsylvania have written back regarding the travel ban. The most frequent target of the group’s ire — U.S. Sen. Patrick J. Toomey (R-Pa.) — responds regularly, often with long letters explaining his positions on family detention centers, gun rights and global warming.

A spokesman for Toomey said the senator’s staff makes sure every piece of mail that comes in is read and receives an appropriate response.

“Senator Toomey believes it is an important aspect of his job,” said spokesman Steve Kelly, and he takes it into account “regardless of whether he agrees.”

Jennifer Fisher, 58, who runs the Postcards for America group on Facebook, said she has received several surprising responses from employees deep within the federal government.

After her group bombarded the Federal Election Commission with postcards demanding stronger protections against foreign interference, an FEC staffer sent Fisher a private message on Twitter to say their postcards were having an effect and suggesting specific targets:

“They are quite powerful,” reads a copy of their exchange. “On this matter, you’ll want to concentrate on commissioners.”

Similarly, a Justice Department staff member emailed Fisher after her group sent a flurry of sympathetic notes to DOJ lawyers, encouraging them to keep doing their jobs despite Trump’s disparagement of their department.

In a telephone interview, the Justice Department employee said she and other lawyers kept the postcards on display for a while in their mailroom.

“We get all sorts of mail at DOJ, and it’s not always kind,” she said, speaking on the condition of anonymity because she was not authorized to speak to members of the media. The postcards were a reminder of who and what they’re working for as DOJ lawyers, she said.

Fisher said the reason her group uses postcards is to avoid security precautions that can often delay letters at federal offices. “But there’s also a whimsical beauty to them, a human element that’s hard to ignore,” Fisher said.

While their goal is to persuade others, many writers say their postcards’ biggest impact has been on their own lives.

Before she joined the Persistent Postcarders, Sue Heckrotte, 70, had never attended a single protest.

“I don’t do well in crowds,” she explained shyly during the group’s recent Friday meetup. The postcards, however, have been a sort of gateway to getting hooked on other activism.

In the past year alone, she has camped outside a legislator’s office and attended three protests. She recently tried calling her senator’s office for the first time to press him on family separations. “It was awkward,” she said. “I kept stumbling over the words.”

And on a recent Friday, as the women’s meeting drew to a close, Heckrotte volunteered to drop off their cards in time for the letter carrier’s 5 p.m. pickup. In her hands, the words of friends felt meaningful, weighty, urgent. But as she walked to a nearby mailbox, she admitted having doubts.

“I honestly don’t know how many minds we’re changing,” she said. “But it’s larger than that. We’re supporting each other with these postcards. We’re making our voice heard. That’s what makes them important.”