After being defeated by 21 votes during the September primary, John DeSimone unveiled Wednesday a write-in campaign against Marcia Ranglin-Vassell, and said he’s running because out-of-town special interests propelled his rival’s victory.

“My opponent has been propped up by special interests,” DeSimone said while standing in a park at the intersection of Branch Avenue and Charles Street in Providence. “She’s not for this neighborhood, she’s for the special interests. And I’m here to fight for my neighborhood, and that’s why I’m running.”

DeSimone objected in part to what he called an undocumented $16,000 independent expenditure in support of Ranglin-Vassell by the New York-based Working Families Party. The progressive group acknowledged it was late in formally filing the expenditure, but noted how the spending had been reported after the primary by RI Public Radio.

“John DeSimone lost his primary because he was out of touch with his district,” Mike Boland, independent expenditure committee treasurer for the Working Families Party, said in a statement. “Now he’s looking for someone else to blame. This is nothing but sour grapes.”

Working Families set up a Rhode Island chapter last year, and this year vowed to become a force in legislative elections. (The independent expenditure on behalf of Ranglin-Vassell was made by the national organization of Working Families.)

Ranglin-Vassell’s narrow defeat of DeSimone, a 24-year incumbent who occupied the second-ranking post in the House of Representatives, was the biggest upset of the September primary.

House Speaker Nicholas Mattiello is now backing Ranglin-Vassell. He’s also supporting Jason Knight, another primary winner, who faces a write-in campaign from Rep. Jan Malik (D-Warren).

DeSimone said he was not aware of any successful write-in campaigns in Rhode Island, but said he hopes to make history as the first. “This is an area where I was born, brought up, raised my family, and I believe that the values of this neighborhood are better served by me running in this write-in campaign,” he said.

He said Ranglin-Vassell didn’t acknowledge support for her campaign by the Working Families Party, and he said the progressive group’s values are not the same as those of residents in House District 5.

Ranglin-Vassell disagreed with the latter point, in a statement: “I ran for state representative because for too long we’ve had politicians who only help themselves and their well connected friends. I believe we need a government that actually fights for all of us. The voters spoke in September and made it clear they want change. I’m disappointed that John is ignoring their will but I will run my campaign on the issues that defined the primary: the need to raise our minimum wage to $15 an hour so families can provide for themselves, the need for ethical oversight of our government to fight corruption and restore trust, and the need to implement commonsense gun reform to help make our streets safe and to protect our children.”

“My volunteers and I are out in the community working hard,” Ranglin-Vassell added, “and I am confident that in November, voters make it clear once again that they want ethical and compassionate government.”

Roland Lavallee, the Republican candidate in House District 5, attended DeSimone’s news conference and said he thinks he’ll benefit from a three-way field in November.

DeSimone has about $46,000 in his campaign account as he embarks on his write-in campaign. As of 2014, he had received more than $200,000 in contributions during his years in office, some of it from unions and other special interests.

DeSimone said some of his supporters told told him they forgot to vote for him, or didn’t disaffiliate after supporting Donald Trump in the primary. “I think the 21 votes is easily overcome,” he said, referring to Ranglin-Vassell’s margin of victory in September.

One of the state’s top political reporters, Ian Donnis joined The Public’s Radio in 2009. Ian has reported on Rhode Island politics since 1999, arriving in the state just two weeks before the FBI...