Abortion rights supporters and opponents are planning hundreds of protests across the country Saturday, an opening battle in the fight over Planned Parenthood’s federal funding.

Anti-abortion protesters planned to picket outside about 200 Planned Parenthood clinics across the country to demand that Congress defund the health care provider.

Pro-choice activists then planned counterprotests. Organizers say the response was massive: Hundreds of different counterdemonstrations, large and small, have been planned across the country.

The context of these protests is a fight for Planned Parenthood’s survival. Republicans in Congress have vowed to pass legislation that bars the family planning provider from accepting hundreds of millions of dollars in federal Medicaid reimbursements. Those reimbursements allow low-income patients to use Planned Parenthood for birth control, screening for cancer or STDs, and other health services — but not for abortion.

Republicans claim that those funds would be redirected to other clinics that don’t provide abortion but that provide some of the same services as Planned Parenthood. But Planned Parenthood plays such a pivotal role in providing family planning to low-income people that it can’t easily be replaced — and a lot of women will get less health care as a result.

A lot of protesters are gathering outside Planned Parenthood clinics — but many are demonstrating in other ways

It’s very possible the pro-choicers will outnumber the Planned Parenthood opponents on Saturday — but you may not always be able to tell just from driving by a clinic. Planned Parenthood has asked supporters to stay away from the clinics and show their support in other ways, not necessarily through loud rallies.

To be sure, there are some big pro–Planned Parenthood rallies, like this one in St. Paul, Minnesota:

This is Minnesota standing today with Planned Parenthood.#RESISTANCE in St. Paul#StandWithPP pic.twitter.com/MBx6X85eC1 — John Nichols (@NicholsUprising) February 11, 2017

And in Manhattan, some demonstrators did end up gathering outside a clinic — with far more supporting Planned Parenthood than opposing it:

Across from Planned Parenthood in Manhattan, abortion rights counter-protest in a moving picket. Clinic door unimpeded. pic.twitter.com/IVrgxcpxGn — Melissa Gira Grant (@melissagira) February 11, 2017

There's the anti-PP protest. They barely have a view of clinic door. More photogs than antis. pic.twitter.com/I5EbR1EaEx — Melissa Gira Grant (@melissagira) February 11, 2017

A coalition of more than 70 anti-abortion groups announced the #ProtestPP actions during the weekend of the Women’s March on Washington. Pro-life activists, it seems, were inspired to do some grassroots protesting of their own. The Women’s March was unapologetically pro-choice and sponsored in part by Planned Parenthood, and may have also been the largest single-day demonstration in US history.

The Women’s March inspired progressives to get more involved in political action at the local level, too. When word got out about the anti–Planned Parenthood protests, activists like Tiffany Caudill in Colorado decided to fight back and organize their own counterprotests.

Caudill set up a Facebook event for a counterprotest to form a human barrier between the anti-abortion protesters and the clinic. Caudill told Vox that she was inspired to take action by the Women’s March, which she had attended with her daughter. “It felt extremely personal” to hear about the anti-Planned Parenthood pickets, she said, after coming back from “this great movement that was all about equality and women’s rights and health care.”

Caudill only expected a few people to commit to coming to join her outside of Planned Parenthood — maybe herself, her friends, and some friends of friends. But after talking to Planned Parenthood representatives, she said she changed her plans.

“Early on we reached out to Planned Parenthood and talked with them about why [counterprotesting is] really not a positive thing to do,” Caudill said. “It can strain their resources, and it’s inevitably not great for patients who are already in a stressful situation.”

Most abortion clinics ask supportive volunteers not to stage counterprotests when they are picketed. It’s well-meaning, but usually counterproductive and even dangerous, writer Lauren Rankin explained at Cosmopolitan.

So Caudill sought ideas for alternatives — perhaps a table for collecting donations, or a letter-writing campaign to Sen. Cory Gardner (R-CO), who opposes Planned Parenthood.

The letter-writing idea took off, and within days, Caudill found herself the co-organizer of a massive rally planned for Saturday outside Gardner’s office. As of Friday, Caudill said, 4,000 people had RSVP’d to the rally on Facebook. Attendees will write Gardner letters to be delivered to his office next week.

Caudill has been politically active her whole life, she said, but more as a protest attendee. For this event she’s working with two co-organizers, Julie Simmons and Liddy Greulich, whom she had never met or talked to before they messaged her on Facebook to offer their help.

“It’s been a huge learning process,” Caudill said. But she expects it to be an “amazing event, with all of us coming together to enact the change we want to see.”

Some activists are spending their Saturday writing Valentine’s Day cards to members of Congress

Similar offsite rallies are happening in a lot of other cities, including a group in New York that has obtained a permit to protest in Washington Square after realizing, due to Planned Parenthood’s requests not to protest at the clinics, that they ought to change their counterprotest plans.

And some activists plan to protest in less visible, but still impactful, ways. Casey Olesko, communications manager at Planned Parenthood Action Fund of New Jersey, said that they decided to put together a simple toolkit to help people hold house parties for writing letters to their members of Congress.

“The response was phenomenal,” Olesko said. “There’s so much grassroots energy. Folks are inviting all their friends and neighbors.”

She estimates that about 130 people have signed up to host events for 1,500 attendees to write “valentines” either thanking their members of Congress who support Planned Parenthood or urging those who don’t to change their mind.

In one way or another, it looks like both supporters and opponents of abortion rights will be carrying the energy of the Women’s March forward this weekend.