Opponents of the natural gas-drilling practice known as hydraulic fracturing, or fracking, will take another major step in building their movement this weekend when they gather in Washington D.C. for a national convergence called Stop The Frack Attack. There will be two days of trainings and workshops, a day of citizen lobbying on Capital Hill and then a rally and march that will deliver toxic fracking waste water to the headquarters of the American Petroleum Institute and the American Natural Gas Alliance. Organizers are expecting upwards of 3,000 people to participate — an impressive number, considering that just a few years ago fracking was something few Americans knew about.

In those few years, however, “fracktavists” have managed to elevate concerns over the air, water and climate impacts of unconventional natural gas drilling from rural kitchen tables to the national stage. They’ve fought tireless state and regional campaigns using a combination of savvy media strategies and good old-fashioned community organizing and they’ve won some significant victories.

More than 200 municipalities, as well as the state of Vermont, have passed ordinances to ban fracking. In New Jersey, conservative Governor Chris Christie has been pressured into signing a one-year moratorium on the practice. Meanwhile, New York Governor Andrew Cuomo has also signed a moratorium, but looks poised to lift it selectively to allow drilling in the state’s gas-rich southern tier. He is already facing heavy criticism and significant political mobilization.

The issue has become so salient in New York that Late Show host David Letterman, known for his reliably light and inoffensive material, went on a strikingly unfunny minute long rant against fracking last week, decrying:

Greedy oil and gas companies of this country have decided that they can squeeze every last little ounce of oil and gas out of previously pumped wells by injecting the substrata of our planet with highly toxic carcinogenic chemicals … they’re poisoning our drinking water … ladies and gentlemen, we’re screwed.

Why did Letterman make this statement now? Maybe fracking just really touches a nerve for Dave, or perhaps he’s trying to keep from being outdone by the likes of Jimmy Fallon, who also recently criticized the controversial gas-drilling practice on his show. Whatever the combination of reasons, it seems pretty unlikely that Letterman would have taken on the power of the fossil fuel industry if he didn’t recognize that he’d have the support of an enormous and rapidly growing grassroots movement.

Up to this point, anti-fracking activism has largely occurred at the state and local level but organizers are hoping that this weekend’s events will help elevate their concerns within the broader national debate about energy and the environment.

According to Lauren Pagel, policy coordinator for Earthworks, Stop the Frack Attack “emerged through conversations with impacted communities, grassroots groups and national environmental organizations … we want to push members of Congress to pass laws that make fracking less dangerous, and make sure the Obama administration is doing the same with their policies. But, we also know that the majority of the regulation of fracking goes on at the state level, so we want to support state efforts as much as possible. “

There’s reason to believe that organizing at all levels can be synergistic. Russell Mendell, an organizer for Water Defense in New York City expressed:

My hope is that our success at stopping fracking in New York will give strength to other fights in other states, but it goes both ways. It’s been widely speculated that Governmer Cuomo will run for president in 2016 and we know he’s keeping an eye on the national conversation. We also know that other states may follow New York’s lead. A big national presence is important for the fight in New York and vice versa.

This recognition that there is strength in a network has allowed the Stop The Frack Attack coalition to grow to include 136 environmental, labor and religious groups of varying sizes. Of course, the diversity of this coalition poses some challenges. There are significant rifts in the movement between those calling for tighter regulation of fracking and those who will not be satisfied with anything less than a complete ban. Pagel recognizes this challenge, but points to the benefits of a “big tent” strategy to advance the common agenda of all of the groups involved.

This sentiment is echoed by Kari Matsko, a 40-year-old project manager for a software-consulting firm who discovered in 2006 that her Lake County, Ohio home was smack in the middle of oil and gas fields leased by her distant neighbors. As Matsko explained:

I was introduced to the risks of oil and gas when I was sickened by fumes from the drilling, my neighbors were a little bit closer to the drill site and they had to evacuate their house. Their children were in the hospital at 3 a.m. It was terrible. … I felt like it was my civic duty to act. I wanted to get the word out there in terms of the risk. No one was conveying the risks. We want to raise awareness and to get information out there and empower people to make informed decisions in the face of all the ads that the industry has been running on TV. … It’s going to be helpful to Ohio … to get attention on the issue and build awareness.

But for Matsko, who now serves on the coalition’s advisory committee, the networking and capacity-building components of the convergence are just as important as the public demonstrations. For her, a successful outcome is one in which “folks are able to walk away with new relationships and new information that may aide in work with their governments. If we can prevent just one case of what happened to me and my neighbors that’s a victory … this mission is ongoing and never ending and these kind of efforts help keep your spirits up and remind you that you’re not alone even if you lose one battle.”