Updated on December 17 at 2:01 p.m. EST

Bernie Sanders hates big money in politics.

Sanders has long insisted he won’t rely on super PACs in his bid to win the White House. The political-spending operations capable of accepting unlimited corporate donations stand as a symbol of the power of money to buy elections. Denouncing them helps Sanders build his credibility as a populist. It has also set the self-described Democratic socialist apart in a field in which many candidates have ties to big-money groups backing their presidential run.

But even for Sanders, escaping the pull of money in politics is not easy.

A few loyal fans of the senator have hit upon the idea of using super PACs as a way to show support. In an odd twist of fate, Sanders can’t do much to stop that. Almost anyone can set up a super PAC, and the outside groups are supposed to operate independently from candidates. That creates a headache for the campaign: Each time a super PAC crops up, Sanders faces pressure to renounce it and ward off charges of hypocrisy.

Sanders’s opposition to super PACs leaves supporters with a difficult choice. Should they renounce super PACs as well, even if creating one could help their favorite candidate? If they make use of one, how do they justify that decision?

Some supporters have taken steps to create super PACs, only to abandon their efforts after realizing it wouldn’t sit well with the campaign. Others have forged ahead with spending operations that qualify as super PACs, while defiantly rejecting the label.

Take National Nurses United, the largest nurses’ union in the U.S. The group endorsed Sanders for president back in August. Its political arm—National Nurses United for Patient Protection—has so far spent more than $550,000 in support of Bernie Sanders, including doling out money for print and digital advertising. The group qualifies as a super PAC, according to the Federal Election Commission. Union organizers, however, reject that name.

“It’s not a super PAC, super PACs are corrupt,” RoseAnn DeMoro, the executive director of National Nurses United, said. “They’re a way for the billionaires to influence the political process and spend unlimited money. This is nurses who want to get our support for Bernie out there. That’s way different than the Koch brothers. This isn’t big money. I think people understand the difference.”

That denial points to a disconnect between public perception of what a super PAC is and how they operate on the ground. Voters often associate super PACs with billionaires and vast sums of corporate money. But not all are alike. The groups can also raise unlimited amounts of money from individuals and labor unions.

“There’s always more nuance to these things when you get away from strict legal definitions and out into the real world,” said Larry Noble, the general counsel for the Campaign Legal Center and former general counsel for the Federal Election Commission. “If you want to look at a report and simply count up the number of super PACs supporting a candidate, that wouldn’t give you a true picture of what’s actually happening.”

On Thursday, Sanders won the support of Communications Workers of America, another major labor union. At an event announcing the endorsement, a similar tension was on display. Sanders denounced big money in politics, but CWA president Chris Shelton indicated the union is likely to use its super PAC to support his campaign. “We will respect Bernie’s wishes, but we will use all legal and possible resources to get him elected,” Candice Johnson, a spokesperson for the union said. “We do have a super PAC, but it’s a super PAC of a union of 700,000 working people, not a couple of billionaires. That’s a big difference.”

Sanders, for his part, has forcefully and repeatedly insisted that he does not have—or want—a super PAC. His campaign has been explicit as well. Earlier this month, after the Associated Press reported that an Oakland-based progressive super PAC plans to spend money in support of Sanders, the campaign emailed supporters with the message: “we don’t want this super PAC’s help.” The campaign has also sent a cease and desist letter to another pro-Sanders super PAC, alleging a violation of federal law.  

Still, when supporters make use of super PACs it can create an awkward situation. If Sanders doesn’t swiftly renounce the activity, it might cost him votes. Forceful criticism, however, could alienate key allies. When pressed, the senator has appeared hesitant to completely disavow the nurses union. “They are nurses and they are fighting for the health care of their people. They are doing what they think is appropriate. I do not have a super PAC,” Sanders told CNN last month.

There’s not much else the campaign can do, apart from sending a signal that Sanders’s opposition to super PACs remains unchanged. “Do I have control over what private people do in the world? No. Do I wish people who want to set up super PACs would do that? No. Do I have any legal recourse as long as they are following the law? No,” Jeff Weaver, Sanders’s campaign manager, said.

Navigating the complicated world of political spending isn’t easy for Sanders supporters either. Chris Pearson, a Vermont state representative who once worked for Sanders’s congressional office in Burlington, says the campaign asked him to shut down a super PAC that he started to bolster Sanders’s White House run. “Frankly, it never even occurred to me that it might make him look bad,” Pearson said, recalling the incident.

Compared to super PACs backing presidential contenders like Hillary Clinton and Jeb Bush, the group had barely raised any money, and Pearson didn’t think his pet project was anywhere near in the same league. He was just hoping to help: “It wasn’t on my mind at all that it might come off as a sort of wink wink, nudge nudge, oh this guy rejects super PACs but now look he has one,” Pearson said. “When it was pointed out to me that way I thought ‘Well, that would be the last thing I’d want to do.’” So he shut the super PAC down.

“I am sure that the concern of the campaign was that Chris Pearson’s relationship with the senator is something people would interpret as being an affiliated super PAC, and that’s not something we would endorse at all,” Weaver said. “Often the media paints all the candidates with the same brush and I categorically reject that assumption. Many candidates running for president have trusted lieutenants who have set up super PACs. That’s not the case here at all.”

Steve Cobble, another ardent Sanders supporter, has a similar story. Cobble is the political director for Progressive Democrats of America, a grassroots organization that supports Sanders. After thinking about how they could best help the candidate, organizers for the group filed paperwork to effectively set up a super PAC. But ultimately, they abandoned the effort. “We realized that Sanders really didn’t want something like that,” Cobble said. “We all agreed that if he wasn’t willing to go down that road, we shouldn’t be the ones to do something different.”

Some supporters harbor concern that staying far away from big money will make it harder for Sanders to win the White House. “It definitely puts him at a disadvantage in terms of the amount of money he can raise, nobody disputes that,” Pearson said. But his loyal followers are quick to defend the integrity of their preferred candidate above all else. “He can’t do anything to stop people from setting up super PACs, so he really is being honest when he says he doesn’t want them,” Cobble said. “If people don’t listen, that’s not his fault.”