In a case that could have wide-ranging implications for the political future of the Service Employees International Union, a former SEIU organizer told a right-to-work group and a best-selling author recently that the union forced him and other workers to volunteer their time for Democratic political campaigns.

On a video segment provided exclusively to The Daily Caller, the organizer says he and other SEIU staff “had to do some political work. We were required as staff to do that.”

The National Right to Work Legal Defense Foundation and Mallory Factor, author of “Shadowbosses: Government Unions Control America and Rob Taxpayers Blind,” obtained an hour-long videotaped statement from the organizer, who now works for a different union.

Factor and the right-to-work group protected the former SEIU organizer’s anonymity by distorting his image and his voice because he fears reprisals from the union.

The SEIU did not respond to questions from TheDC about whether it routinely requires its organizers to devote their time to political campaigns.

But the union’s leaders, the organizer said on the video, “would tell us, ‘We need to go canvassing for this candidate, so we need you to sign this sheet to say that you are requesting a personal day today, so that you can go do this. We’ll make it up to you later,'” he said in the interview.

“And I [thought], ‘Is this really legal? Can you require me to volunteer for a candidate that I can’t even vote for?'” he recalled thinking. “I don’t live in that jurisdiction, that district that they are running from.”

“And that happened a lot around election time. The staff was — it was — I called it ‘mandatory volunteerism.’ And that happened to everybody. We were all told that we had to volunteer for this candidate on this day.”

National Right to Work Legal Defense Foundation spokesman Patrick Semmens said the interview, which took place less than a month ago, confirmed what his organization has long known.

“I wish it were surprising that the SEIU was coercing this organizer into supporting union boss politics, but these days that’s standard operating procedure for Big Labor,” Semmens said in an email to TheDC.

“Organized labor’s mission has almost completely morphed from representing workers on the shop floor to pushing left-wing politics. The only difference between Big Labor and other political groups is that union officials get to force workers to contribute, instead of relying on voluntary contributions.”

Factor, too, was outraged. “It’s FEC fraud,” he told TheDC, referring to the Federal Election Commission. “Whatever it is, it’s definitely not playing by the rules. Unions tend not to do that.”

He said the former SEIU organizer featured in the video is “willing to testify in front of Congress as long as his identity is kept secret.”

Allegations of union-mandated political activity are nothing new. In “Shadowbosses,” Factor writes that unions’ “grassroots organizing work” is often “performed by union members who can be paid to volunteer.” (RELATED: Book: Obamacare law designed to unionize 21 million health care workers)

The FEC, he writes, “does not allow volunteers for federal candidates, including Presidential candidate[s], to be paid by third parties for volunteering, and state laws vary on the point. But the unions get around these rules by compensating volunteers to do general political organizing work and get-out-the vote efforts for the benefit of specific candidates.”

Unions, he adds, “try to keep the fact that they pay their political volunteers a secret,” offering “expense reimbursement and stipends to members who act as political volunteers.”

He points to the Ohio Civil Service Employees Association, a union of state and government employees in the Buckeye State, whose website offered “a $25 stipend” in 2004 for union members who helped with “GOTV [get out the vote] phone banks … to ensure that we Take Back Ohio.”

In 2006 the same union’s website sought “volunteers” who would receive “a cell phone, money for mileage, and meals [and] … a $50 stipend” for Election Day work in conjunction with the AFL-CIO. “They are looking for members to visit precincts, talk to voters, and identify problems,” the union said.

“AFSCME Ohio 8,” Factor explained in his book’s footnotes, “offered $25 gift cards to people who got out the vote. Its website reported, ‘Members of Local 1846 Athens Public School Employees, Local 1699 Ohio University Employees, and Local 1252 members from O’Bleness Hospital are doing their part get people to the polls—and receive a $25 ‘Turkey’ gift card.'”

At New Jersey’s largest state university in 2010, the American Federation of Teachers paid its members “$50 stipends for labor walks and $25 stipends for phone banks.” The Committee on Political Education of the Union of Rutgers Administrators announced this incentive on its website.

Factor referred TheDC to a Web page from that Rutgers union offering a “$50 stipend per walk” along with t-shirts and free raffle tickets for “a 42 [inch] flat screen TV and a Garman [sic] GPS.”

Last year the Union of Rutgers Administrators paid “a $25 stipend for phone banking and $50 for labor-to-labor walks” designed to persuade union members to vote for “our issues.”

In another case of a union member supporting a political campaign as a condition of her membership, a delegate to the national convention of the National Education Association, the largest U.S. teachers union, said February in congressional testimony that the NEA required her to contribute money to Democratic candidates — and did so in her name on one occasion without her permission.

The House Committee on Oversight and Government Reform published statements from three union members who objected to seeing their union dues diverted to support political candidates they did not support.

Claire Waites, an eighth grade science teacher in Baldwin County, Alabama, told the committee that during the union’s 2004 convention, the NEA instructed her to donate to a “Children’s Fund,” and directed her precisely how to contribute.

That fund, she later learned, contributed the funds toward the presidential campaign of Democratic Massachusetts Sen. John Kerry. (RELATED: Supreme Court rules 7-2 against SEIU on forced contributions)

“I felt a wave of illness come over me like none I had ever felt before,” Waites, a Republican, testified. “These who were supposed to be my people duped me into donating to a candidate I was voting against.”

Four years later, she learned during the 2008 NEA convention that Saaida Hunter, her county’s union president, had contributed again to the same fund “using the money Hunter had withheld from our travel money provided by the local.”

In a later conversation with Alabama state NEA president Peggy Mobley, she recalled in her testimony, she explained that “my Children’s Fund contribution was made without my permission and I wanted my money back.”

“She refused,” Waite recalled, “and told me they did not do that.”

Hunter, she said, later told her “that my contribution would go to the Obama campaign, another candidate I did not support, and that contributing in my name was probably illegal. … Needless to say, I never got my money back.”

Factor added in a subsequent interview that if President Obama is re-elected, “it will be because of the unions. Our first union-label president will owe them big-time. He’ll be paying them back, and it sure won’t be with more investigations and scrutiny. There will even be less.”

Follow David on Twitter