BOSTON — Massachusetts passed its universal health coverage on April 12, 2006. The day after, a cross-section of health-care providers, consumer advocates and businesses huddled on the 11th floor of a Boston office building.

All health reform supporters, they gathered to discuss one question. “The question was, what can we do to educate the public?” recalls John McDonough, who teaches at the Harvard School of Public Health. “Then we pretty much went about explaining to the state what this law was.”

It’s a question the White House now finds itself grappling with, too, as it looks to publicize a law that few Americans understand. It’s now taking flak for awarding a $20 million public relations contract to highlight the Affordable Care Act’s benefits.

Republicans have blasted the contract as wasteful, a political ploy to hype a polarizing law. Historically, there has been a bipartisan distaste for this kind of investment: Democrats blasted President George W. Bush when he used government funds to promote Medicare’s new prescription drug benefit in 2004.

Architects of the Massachusetts reforms, however, say this is the exact kind of investment that the Obama administration needs to make right now — and hasn’t done enough of yet. As they learned from experience (and I’m now learning on a week-long trip to Boston, sponsored by the Kaiser Family Foundation), making an insurance expansion work hinges in no small part on making sure people actually know about it.

When Massachusetts passed its law in 2006, the state spent $4 million on publicity and outreach. The Connector, the newly created entity to oversee the insurance market, ultimately hosted 150 events across the state. It partnered with local grocery stores, pharmacies and even the Boston Red Sox to get the word out about what the law changed, and how people could enroll.

Just about everyone involved in the effort agrees it was a necessary, and successful, investment. Massachusetts’s uninsured rate fell from 10.9 percent in 2006 to 5.5 percent in 2007. Those signing up were traditionally the most difficult to reach: low-income individuals who may have never before interacted with the private insurance system.

“There was a tremendous amount of outreach, by community-based organizations, and millions in dollars of grants to do this,” says Harvard University’s Nancy Turnbull, who also sits on the Connector board. She remembers about 60 percent of those who signed up were contacted by an individual involved in state outreach efforts.

Romneycare isn’t a perfect analogy to Obamacare. As Jonathan Cohn points out, the Massachusetts law never faced the intense opposition that the federal overhaul has. Promoting the law has become political in a way it never really did in Massachusetts.

Business groups, meanwhile, haven’t stepped up in implementing the federal law as they did in the Bay State. “It’s like they went into a rabbit hole and after, supporting the law, ignored the need to do real education,” says McDonough.

There is one nonprofit, Enroll America, that has promised to play a significant role in the task, but that’s pretty much it. The work that it does, alongside the Obama administration, will largely determine how big the Affordable Care Act’s insurance expansion actually is.

CBO estimates that the health-reform law will cover 32 million more Americans by 2019. But that still leaves about 16 million Americans, many of whom might be eligible for public programs, uninsured. The CBO, for example, expects that nearly 6 million of those newly eligible for Medicaid just won’t sign up for the program.

Massachusetts managed to enroll nearly all of its uninsured into health coverage with an intensive outreach campaign. The Medicare prescription drug program that President Bush promoted? It now has 22.5 million members and is incredibly well-liked by seniors.

So far, McDonough says he hasn’t seen “anything in the way of sustained, public education” coming out of Washington. This new $20 million investment could be a part of that campaign — and a part of the Affordable Care Act’s ultimate success.