“They really dislike dark money and any type of political spending,” Ms. Muller said of voters. At the same time, she noted, research suggests “voters trust outside-group ads more than they trust candidate ads.”
Mr. Dach said that the network of state groups had bolstered the Hub Project’s credibility with voters, connecting it with local activists who in some cases ended up starring in ads. Mr. Dach, a former Obama administration health care official, said the 14-month advocacy campaign had helped keep policy at the forefront of the midterm election.
Mr. Dach and Mr. Gerney both said they decided to go on the record with the details of the campaign because they hoped Democrats would adopt it for future election cycles. In the past, Mr. Dach said, Democrats had lacked the funds and focus to sustain an argument on core issues like health care.
“These issues are clear, they’re understandable to people, but I think we neglected and we were financially unable to sustain this kind of work before,” Mr. Dach said. “We have been on the same message — pre-existing conditions, age tax, health care costs, sabotage — from day one.”
The event in Bradenton Beach taunting Mr. Buchanan was emblematic of the group’s approach — and its limitations. Democrats had been hopeful of flipping the conservative-leaning district, anchored in the comfortable and predominantly white suburbs on the south end of Tampa Bay. A prominent local trial lawyer, David Shapiro, jumped in as the Democratic candidate and the race intensified after a Hub Project researcher discovered Mr. Buchanan’s yacht purchase.
Yet as voters on the right have grown more energized about the midterm elections, Mr. Buchanan has appeared somewhat more secure in his re-election prospects. As Mr. Fitzgerald assailed the Republican’s voting record, flanked by an activist dressed as a yacht captain, Vince Cavell looked on skeptically from a short distance.
Mr. Cavell, 66, who retired to the area after a career in the computer business, shrugged at the attacks on Mr. Buchanan’s support for the tax law.
“I’m enjoying the lower taxes,” he said.