In March, I was honored to watch President Obama's bill signing for the Patient Protection and Affordable Care Act with a group of labor leaders and reform activists. Around me were advocates who had worked for months -- in some cases decades -- to bring about health care reform. At The Atlantic Philanthropies , we made a big bet on health care, investing significantly in organisations like HCAN because we believed that this was a singular opportunity to get health care done.

The reality, though, is that we aren't done. As big a victory as this was -- and it was the largest expansion of the social contract since Medicare -- getting health care right could be harder than getting it passed. And the lessons of health care reform are going to resonate for years to come, in the immigration debate and beyond.

Last month Atlantic gathered a panel of ten leading voices on health care including Richard Kirsch of HCAN, E.J. Dionne of the Washington Post, John Rother of the AARP and Judy Feder of Georgetown University and the Center for American Progress to assess what we learned from the campaign, and what challenges lie ahead.

What We Learned

In the responses from these ten diverse and informed advocates (click over to our website to see their contributions ) three clear themes emerged. What is evident is that these learnings are instructive for any movement for social justice, not just health care.

1. Grassroots organizing worked. "The power of organizing," writes Deepak Bhargava , Executive Director of the Center for Community Change , "is perhaps the single most important lesson learned from the health care debate. Grassroots organizing brought health care reform into reality, just as town hall protests and local opposition on the other side nearly killed the bill."

When anti-reform advocates hijacked the debate last August, organizations like HCAN organized pro-reform turnouts. As elected officials wavered, advocates coordinated petition drives and a march. And when the prospects for reform looked bleak, we increased our investment in the national field effort. Grassroots organizing made the difference.

2. The voices of ordinary people played a decisive role. In March I wrote about an insurance victim who had campaigned vigorously for reform. "I am elated," he told us. "I weep that this didn't happen in time to save my son. But I kept my promise to him. I helped to pass this bill."

In a campaign focused so heavily on filibusters and CBO scores, those most affected by the broken health care system were the backbone of the campaign. They were the messengers who demonstrated the moral case for reform. In the ongoing debate over health care, and on issues like immigration, we must elevate the voices of those who need reform most urgently.

3. Keep coming at them. The Washington Post's E.J. Dionne tells the story of his son's little league coach, who rallied his team with a simple reminder: "You strike out with the bases loaded. What do you do? Keep coming at them! You drop a fly ball and let two runs in. What do you do? Keep coming at them!"

Like an action hero that just wouldn't fall, health care reform advocates just kept coming at them. As Judy Feder, a veteran of the Clinton Administration's health care effort noted , "The lesson from this campaign," she writes, "Is that if we stick together and bring to bear all our resources ... we can make change happen. The health reform campaign ... used all the tools in our arsenal - research, communications, advocacy and political engagement."

What Now?

As much as we'd love to declare victory and take the summer off, we have to make sure the implementation phase of health care reform gets done right. We need to ensure that people see the benefits of reform personally -- and soon. This week Medicare beneficiaries will see the first $250 rebate checks, but that is just the beginning of a multi-year effort to put the new law into action.

"The task ahead," writes Debra Ness , President of the National Partnership for Women and Families , "is to do nothing less than transform the way our health care system delivers care. There are many who say it can't be done, that you can't improve quality and get costs under control. But that's exactly what we need to do -- and we can do it if we apply the lessons of the fight for reform, and refuse to give up until we realize the law's promise."

At Atlantic, our grantees are deeply involved in implementation, not only to fight rear-guard actions to repeal health care, but to assure its thorough and fair implementation, particularly for children and older adults. There are communications challenges, explaining what's in the bill to a skeptical public. And as Debra writes, there are practical challenges in making sure that 30 million people are added to the health care rolls efficiently.

We have learned that there is no sustainable progress without social movements. With health care on the books, a new chapter in this movement begins -- an ongoing campaign to ensure that those who need reform the most are seeing tangible benefits from this bill. For advocates working on other movements for social justice - immigration, women's rights, gay & lesbian rights, aging - health care reform could offer a blueprint, with lessons that will echo for decades.

I invite you to read our forum and share your comments. Below is a video featuring three of our respondents -- E.J. Dionne, Judy Feder and Richard Kirsch -- discussing how the politics of health care could play out in the months to come.

Follow us on Twitter - @atlantic .

Note: This post has been updated since originally posted.