Cassidy & Associates President Barry Rhoads talks about the government shutdown for a video for the lobbying firm’s Web site. (Evy Mages/FOR THE WASHINGTON POST)

In 1981, lobbyist Gerald Cassidy and his client, Hal Thorkilsen, the chief executive of Ocean Spray, marched into the Old Executive Office Building next to the White House, armed with a cardboard box filled with two pitchers and a can each of frozen cranberry and orange juice.

They had scored a meeting with Vice President George H.W. Bush and a member of his staff, who were deciding the fate of a proposed regulation that would have made Ocean Spray label its marquee product, frozen cranberry juice, to indicate it had less juice and more sugar than orange juice — a change that would have dealt a huge blow to Ocean Spray’s consumer appeal.

“We showed up with a container of water and mixed the two products in front of them and said, ‘This one is cranberry juice cocktail, this one is orange juice, and they both have the same amount of sugar in them. You can see they both have the same amount of water because we just put it in.’” Cassidy recalled. “The fruit particles in both products were roughly the same, there was no nutritional difference. It didn’t seem fair to us that one should be labeled 100 percent juice and the other should be labeled 30 percent juice.

“That made perfect sense when you could see a visual image of it,” he said.

The regulation was shelved.

Today, Cassidy is still Ocean Spray’s hired hand in Washington. But his firm is selling the company’s message in a very different way. This month, Donna Denisen, a vice president at Cassidy & Associates and an Ocean Spray lobbyist, did an on-camera interview with a cranberry grower wading through a makeshift pool of cranberries at Union Station, to talk about the farm bill. The event drew several lawmakers, and the four-minute video was posted on YouTube, inviting viewers to visit Cassidy’s Web site, which firm leaders have spent the last year overhauling to attract more lawmakers and potential clients through Twitter, Facebook, LinkedIn and YouTube.

The two lobbying strategies, deployed 32 years apart, are snapshots of the old way and the new way of doing business on K Street. What was once a behind-the-scenes business is evolving to appeal to public opinion in the Internet age. And with the lobbying business at a standstill, even superstars such as Cassidy — one of the most successful lobbyists of his generation — are having to embrace new ways of reaching policymakers and clients to protect their bottom line.

“We used to do those kinds of things,” Cassidy said of the 1981 frozen cranberry juice demonstration. “Today, you need a lot more public information to carry your position. If you look at food labeling today, there’s so much going on you couldn’t expect to get a meeting like that anymore. So the way to affect it is to go out there and get public attention and hope you reach some of the decision-makers through this attention.”

The strategy

In 2012, Cassidy & Associates earned barely half of what it did a decade earlier in lobbying fees — $15.5 million compared with $28.7 million, according to the Center for Responsive Politics. To offset the losses, the firm has begun branching out into non-lobbying work, including consulting for foreign businesses and governments.

Still, it took some convincing to get Cassidy to see how a digital strategy could help his business.

“At first I didn’t fully understand it,” he said. “I didn’t know who you reach with these sites.”

He turned to Tom Alexander, his communications consultant, for help.

“We were talking about the economy and the reduction in business in the lobbying field, and how we needed to reach out more and get our story told,” Cassidy said. “Tom directed us to this approach.”

They began closely tracking how many people visit their Web site. Between September 2012 and September 2013, the number of visits jumped 32 percent, and people were staying on the site an average of 12 percent longer — about two and a half minutes. And they launched an online video series, “The Insiders,” in which the firm’s advisers share their thoughts on politics and current events — most recently, sequestration and the government shutdown.

“We wanted to get our experts out in front of people,” Cassidy said. “It was an important way to reassert our firm’s relevance in Washington.”